The full decklists have already been spoiled, and I'd like to take a guess at the potential the new cards have in other formats.
Below are my speculations regarding their playability, and I'd love to receive your opinion too.
Grasp of Fate (aka who needs Banishing Light) is probably going to be a white EDH staple, so its price will most likely be high as a single buy.
Righteous Confluence - This card will mostly be enchantment removal with some OK secondary effects. I'm not a fan.
Bastion Protector - Indestructible or not, -3/-3 on this guy and your commander protection is gone. Not a very good card in my opinion.
Dawnbreak Reclaimer - Might be nice if you don't run a lot of creatures, or run graveyard hate... It would be hilarious seeing the look of an opponent's face trying to choose between the only two creatures in my graveyard, Blazing Archon and Avacyn, Angel of Hope.
Mystic Confluence - I see it as a budget version of Cryptic Command. Probably not going to see play in high levels, but has good potential for moderately priced EDH decks.
Synthetic Destiny - As already mentioned in threads in this forum, it's probably going to see play in crazy blue combo decks, with various ways to make tokens and fatties to summon to the battlefield at instant speed. Kind of reminiscent of Day of the Dragons.
Corpse Augur - Like a Grim Flowering for 4 that also causes you to lose life. The closest thing we had to this was Disciple of Bolas, which favored fatty decks, while this one definitely favors graveyard shenanigans. Probably going to be a graveyard deck staple in EDH.
Daxos's Torment - I definitely see a potential for this card to be competitive. Pairing it with cards like Bitterblossom and Master of the Feast can create some scary early pressure based on enchantments. We'll just have to see if it's good enough for Vintage & Legacy... Probably not.
Scourge of Nel Toth - At first I was really excited for this card because it had dirt cheap reanimation, but after seeing that people here argued that he's just a big body I kind of have to agree that this guy probably won't be seeing Legacy play. In comparison to dredge classics like Stinkweed Imp this card still doesn't do enough, but either way it's going to wreck some face in dredge EDH builds.
Wretched Confluence - Interesting EDH card but probably not going to see too much play.
Magus of the Wheel - A really cool card that makes Wheel of Fortune accessible to you, even if you don't have several hundred dollars. Definitely going to see play in red EDH decks, although it's probably too slow for Legacy - it needs to survive one round to do its thing, and that isn't too common.
Dream Pillager - An interesting source of card advantage with red flavor. However, red doesn't really have the mana to cast all that bunch of stuff, so maybe RG will find a use for this card...
Rite of the Raging Storm - Multiplayer has just gotten a lot more awesome. It would be hilarious seeing everyone have a copy of this card, so that on each player's turn he gets 3 5/1 elementals that can't attack anyone.
Fiery Confluence - I love the versatility on this card, but of course it's only viable for EDH. The first and third options will probably be mostly used.
Mizzix's Mastery - Did someone counter your Enter the Infinite? No prob! Got 8 mana? Play ALL the cards!!! If an EDH deck uses red and it doesn't focus on creatures, it's probably going to run this. Perhaps it might even be useful for Legacy Storm?
Bloodspore Thrinax - Combos too easily with persist creatures like Kitchen Finks and Woodfall Primus. Since it's 4 CMC it isn't going to replace Melira, but it's definitely going to buff some EDH decks based around them.
Pathbreaker Ibex - This guy is like Craterhoof Behemoth's younger brother, only favoring fattie decks instead of token decks. Will definitely see play in Mayael the Anima and several other fattie-favoring commanders.
Blade of Selves - Have you got big ETB creatures, or just big creatures? This card is an EDH staple for you. The equip cost might be 4, but it's well worth it. Just think of getting 2 extra Rune-Scarred Demons or Baneslayer Angels on each attack.
Scytheclaw - Like Quietus Spike, but more mana expensive. Unless a deck has a lot of trample, I see no reason for it to run this.
Thought Vessel - 2 CMC mana rocks are hard to find and very helpful, and that includes this one. Blue draw-power EDH decks will probably want to run this consistently, and if several Legacy decks run Mind Stone I can also see them pondering running this card.
Daxos the Returned - WB stax just got waaaay more annoying. The worst thing is that Teysa, Orzhov Scion benefits from Daxos's creatures in both her abilities, so if you play both in your deck your opponent will probably not have much creatures on the board. Ever.
Ezuri, Claw of Progress - Yeah, yeah, Animar, Soul of Elements FTW, Edric, Spymaster of Trest wins so hard, bla bla bla. This little punk can help UG (with its various tokens and utility creatures) to wreck face, so prepare your helmets! At least this card can't be played in Tiny Leaders.
Kalemne, Disciple of Iroas - As has long been speculated, this girl will make a fine commander for a Giant tribal, which is now pretty darn viable with that Urza's Incubator reprint. I'm looking forward to seeing how frightening a good Kalemne deck will be!
Karlov, Ghost Council - This creature might be a pretty big annoyance in Oloro, Ageless Ascetic decks, but probably nowhere else in EDH. Tiny Leaders might serve this guy better for a deck of his own, though.
Kaseto, Orochi Archmage - Probably going to see a million versions of decks for this guy, whether if they're going to be Snake Tribal, Snake Unblockables, or just Unblockables. The fact that this guy can lead a Tiny Leaders deck will further blow things up for him.
Mazirek, Kraul Death Priest - A commander ideal for either Golgari combo Ghave, Guru of Spores-ish builds with persist (again), or as a stax commander growing larger for every casualty on the board. Probably more likely to be the former (5 CMC for a 2/2?! Seriously?!).
Meren of Clan Nel Toth - I'm really conflicted about this card. On the one hand it's a viable (albeit not amazing) commander. On the other hand, it's phenomenal in combo graveyard builds (where the CMC limit doesn't really apply). Viable in Vintage? Not really. Viable as a commander? Probably. Going in my Karador, Ghost Chieftain deck? Heck yes!
Command Beacon - Apparently only to be printed in the Izzet deck, this land can enable some serious commander play, even if you already played it a dozen times from the command zone. In fact, this can almost grow to be a second Command Tower-like EDH staple.
So yeah, that's my opinion on the cards! What do you guys have in mind?
It honestly doesn't matter what Mazirek's base power and toughness are. If you can't respond to lethal damage aimed at him with a ludicrous amount of sacrifice triggers, then you're doing it wrong. Heck, if you cast him, and he (and the rest of your team) is not several times bigger than he was originally by the time it comes back around to your turn, then you're probably still doing it wrong.
You missed Skullwinder, which is basically a splashable Eternal Witness with upside in 3+ player matches. Don't sleep on it, it's damned good. Fiery Confluence will also see play in normal FFA Multiplayer - it's a double Sizzle for one mana extra in Sulfuric Vortex decks, for one.
Below are my speculations regarding their playability, and I'd love to receive your opinion too.
Righteous Confluence - This card will mostly be enchantment removal with some OK secondary effects. I'm not a fan.
Bastion Protector - Indestructible or not, -3/-3 on this guy and your commander protection is gone. Not a very good card in my opinion.
Dawnbreak Reclaimer - Might be nice if you don't run a lot of creatures, or run graveyard hate... It would be hilarious seeing the look of an opponent's face trying to choose between the only two creatures in my graveyard, Blazing Archon and Avacyn, Angel of Hope.
Shielded by Faith - an Indestructibility that's amazing for enchantress decks, since its second ability overrides Argothian Enchantress's Shroud. Can potentially see play.
Synthetic Destiny - As already mentioned in threads in this forum, it's probably going to see play in crazy blue combo decks, with various ways to make tokens and fatties to summon to the battlefield at instant speed. Kind of reminiscent of Day of the Dragons.
Daxos's Torment - I definitely see a potential for this card to be competitive. Pairing it with cards like Bitterblossom and Master of the Feast can create some scary early pressure based on enchantments. We'll just have to see if it's good enough for Vintage & Legacy... Probably not.
Scourge of Nel Toth - At first I was really excited for this card because it had dirt cheap reanimation, but after seeing that people here argued that he's just a big body I kind of have to agree that this guy probably won't be seeing Legacy play. In comparison to dredge classics like Stinkweed Imp this card still doesn't do enough, but either way it's going to wreck some face in dredge EDH builds.
Wretched Confluence - Interesting EDH card but probably not going to see too much play.
Dream Pillager - An interesting source of card advantage with red flavor. However, red doesn't really have the mana to cast all that bunch of stuff, so maybe RG will find a use for this card...
Rite of the Raging Storm - Multiplayer has just gotten a lot more awesome. It would be hilarious seeing everyone have a copy of this card, so that on each player's turn he gets 3 5/1 elementals that can't attack anyone.
Fiery Confluence - I love the versatility on this card, but of course it's only viable for EDH. The first and third options will probably be mostly used.
Mizzix's Mastery - Did someone counter your Enter the Infinite? No prob! Got 8 mana? Play ALL the cards!!! If an EDH deck uses red and it doesn't focus on creatures, it's probably going to run this. Perhaps it might even be useful for Legacy Storm?
Centaur Vinecrasher - This card can be a horrifying beater in Titania, Protector of Argoth and Borborygmos Enraged decks, and maybe-not-really an option in Scapeshift decks. In fact, this guy is an excellent finisher for any stax deck running green.
Pathbreaker Ibex - This guy is like Craterhoof Behemoth's younger brother, only favoring fattie decks instead of token decks. Will definitely see play in Mayael the Anima and several other fattie-favoring commanders.
Scytheclaw - Like Quietus Spike, but more mana expensive. Unless a deck has a lot of trample, I see no reason for it to run this.
Seal of the Guildpact - This card, on its own, can make dual-color just as viable as tri-color in EDH, in my opinion. Getting an extra 2 on Rakdos's Return, making Grand Arbiter Augustin IV that much more annoying, getting Oona, Queen of the Fae some turns earlier... it's all within your grasp.
Thought Vessel - 2 CMC mana rocks are hard to find and very helpful, and that includes this one. Blue draw-power EDH decks will probably want to run this consistently, and if several Legacy decks run Mind Stone I can also see them pondering running this card.
Arjun, the Shifting Flame - Pretty cool card, but why so expensive?! Niv-Mizzet, the Firemind and Nekusar, the Mindrazer decks might take a big liking to him, but otherwise this card is probably not going to be a hit.
Daxos the Returned - WB stax just got waaaay more annoying. The worst thing is that Teysa, Orzhov Scion benefits from Daxos's creatures in both her abilities, so if you play both in your deck your opponent will probably not have much creatures on the board. Ever.
Ezuri, Claw of Progress - Yeah, yeah, Animar, Soul of Elements FTW, Edric, Spymaster of Trest wins so hard, bla bla bla. This little punk can help UG (with its various tokens and utility creatures) to wreck face, so prepare your helmets! At least this card can't be played in Tiny Leaders.
Kalemne, Disciple of Iroas - As has long been speculated, this girl will make a fine commander for a Giant tribal, which is now pretty darn viable with that Urza's Incubator reprint. I'm looking forward to seeing how frightening a good Kalemne deck will be!
Karlov, Ghost Council - This creature might be a pretty big annoyance in Oloro, Ageless Ascetic decks, but probably nowhere else in EDH. Tiny Leaders might serve this guy better for a deck of his own, though.
Kaseto, Orochi Archmage - Probably going to see a million versions of decks for this guy, whether if they're going to be Snake Tribal, Snake Unblockables, or just Unblockables. The fact that this guy can lead a Tiny Leaders deck will further blow things up for him.
Mazirek, Kraul Death Priest - A commander ideal for either Golgari combo Ghave, Guru of Spores-ish builds with persist (again), or as a stax commander growing larger for every casualty on the board. Probably more likely to be the former (5 CMC for a 2/2?! Seriously?!).
Meren of Clan Nel Toth - I'm really conflicted about this card. On the one hand it's a viable (albeit not amazing) commander. On the other hand, it's phenomenal in combo graveyard builds (where the CMC limit doesn't really apply). Viable in Vintage? Not really. Viable as a commander? Probably. Going in my Karador, Ghost Chieftain deck? Heck yes!
Mizzix of the Izmagnus - First of all, this name breaks my teeth every time. Secondly, THANK YOU WIZARDS for printing a commander that makes Storm a viable strategy! I can definitely see this guy juggling cantrips all day long, while Young Pyromancer, Guttersnipe, Talrand, Sky Summoner, Sphinx-Bone Wand and the like have a field day.
Command Beacon - Apparently only to be printed in the Izzet deck, this land can enable some serious commander play, even if you already played it a dozen times from the command zone. In fact, this can almost grow to be a second Command Tower-like EDH staple.
So yeah, that's my opinion on the cards! What do you guys have in mind?
Wheel of Fortune isn't hundreds of dollars.
Fiery Confluence will also see play in normal FFA Multiplayer - it's a double Sizzle for one mana extra in Sulfuric Vortex decks, for one.
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