The official EDH forum is getting the reddit hug of death right now, but word is that the mana generation restriction is removed. This means that tapping City of Brass for green or white produces green or white. You can make mana outside your color identity now. Matter Reshaper and other {C} costs will be harder to play.
Also Vancouver mulligan with one free mulligan to 7 is official, so manabases might need to be changed accordingly.
Edit: Managed to get the text of the announcement.
Rule 4:
We still love Rule 4. It's a nice piece of flavor and reinforces the idea that this format goes beyond simple mechanical restrictions into a deeper philosophical approach around color and mana symbols. Its effect on the game was pretty small, but that flavor message made it worthwhile to preserve.
However, the mana system of Magic is very complicated, and trying to insert an extra rule there has consequences in the corners. Harvest Mage. Celestial Dawn. Gauntlet of Power. And now, colorless-only mana costs.
Being able to generate colorless mana more easily in Commander wasn't going to break anything. But, it represented another "gotcha" moment for players, who were now likely to learn about Rule 4 when someone exploited the colorless loophole. We could paper over it (both "mana generated from off-color sources can only pay generic costs" and "you can't pay a cost outside your color identity" were considered), but a lot of the flavor would be lost in the transition, defeating the purpose. Without the resonant flavor, Rule 4 was increasingly looking like mana burn - a rule that didn't come up enough to justify it's existence.
We don't expect removing the rule to have a big impact. Some Sunburst and Converge cards might get a bit more of a look. Sen Triplets works more like you'd expect, as does Praetor's Grasp. The clone-and-steal deck, already one of the most popular archetypes, gets better, but less than you might think. It turns out there really aren't that many impactful non-blue activated abilities on cards that commonly get stolen in Commander. It's OK if you can regenerate that creature you just stole, and you'll need to work for it a bit anyway.
One side benefit to the removal of both the color production and mulligan rules is that, in terms of game play, Commander becomes a normal game of multiplayer Magic with a higher life total and a set of additive rules to bring a new piece (your Commander) into the game. That's good streamlining in terms of teaching people the format and reducing gotcha moments while still preserving the essential flavor of Commander.
We also have City of Brass by virtue of tapping it for white or green, which becomes colorless because it's outside Marchesa's color identity, unless that rule changes.
I think we have something new to test out in Matter Reshaper. We have enough colorless mana to support it, and he's card advantage that we can repeat, plus the occasional free creature.
The cutoff for the ability is at 3cmc, but the deck is built with a lot at 4CMC for fleshwrither/dimir house guard tutoring. I guess it's at least a free card, though, and would put lands onto the battlefield for free.
Dualcaster is an infinite combo with Living Death:
Cast LD, Cast Dualcaster, Dualcaster enters, copy LD, sac Dualcaster, and repeat to get infinite ETB/LTB effects (or as many as you want there to be, because you can halt it). Could win off of Gary ETBs, one sided board wipe off of Nevermaker/Venser, infinite mana from Phyrexian Altar. You could exile each opponent's grave off of Agent of Erebos so only you are left with a board.
Unfortunately, they're on an Ally kick right now, so it's likely that an ETB effect will require/be strong only with Allies or be overcosted because this limited environment is teeming with Allies and it would be oppressive if it weren't expensive.
We'll see, though. We did get new Drana last set, and she's a second lieutenant like Mikaeus is.
Ok, it has to be said
Stop hijacking this thread
Please keep your future set discussion to the proper forum, they have no relevance to Marchesa decks.
The fact that several cards that are in this deck are about to get errata to a new mana symbol is quite relevant. {C} mana costs could become relevant to the deck in the future. The fact that two discussions about the <> symbol have taken place so far, once when it was initially leaked and once when talking about filters, means that it's relevant to state plainly what the <> symbol is now that we know. It's not "future set discussion", it's discussing something that's of fundamental importance to EDH.
Btw, for anyone curious, Wastes is just a card name. It does not work like other basics, there's no implied "tap for C". The full art ones are basically textless promos, the regular ones will always have "Tap for C" as their rules text. So there's no big change to how basics work coming.
EDIT: lol looks like mtgsalvation has a symbol to update.
The only real difference is that Wastes doesn't have a type and therefore doesn't affect Domain. It's not a color so it doesn't affect Converge, either. This means that Command Tower (and everything else that says "any color") doesn't make {C}. It's a pseudo-color, only in the sense that it shows up in mana costs.
I don't think anything here precludes Wastes from having oracle text of "(tap for C)" like other basics do (ie. reminder text styled inside parentheses)".
With the spoiler of the Expedition Mystic Gate, it looks like <> will indeed be the new symbol for colorless mana. As such, should we take the earlier suggestion and find a spot for the filter lands in order to prepare for any future colorless costs?
If that Mystic Gate is real, then every colorless mana ability will produce <> (ie. Sol Ring will make <><>, Ancient Tomb will make <><> and shock you for it, Phyrexian Tower will make <>, Reflecting Pool makes it if you control a land that makes <>, Pain Lands make <>). It's not that the filter lands are the only ones that will do this.
The remaining question is whether colorless is a color or not, ie. whether Command Tower taps for WUBRGD or just WUBRG. Reflecting Pool would work regardless because it makes mana of "any type", not "any color".
Sol Ring doesn't tap for generic mana. Sol Ring taps for colorless mana. Generic mana is the 2 that's in the mana cost of Damnation, and may be paid for with WUBRG or colorless mana. Generic mana only exists in mana costs of spells and abilities. Rules text of things that make {1} make "1 colorless mana" (see old versions of Sol Ring and Ashnod's Altar). Sol Ring doesn't produce generic, it makes colorless. The current way of writing this is to use {1} for either colorless or generic, which is confusing in that the {1} in generic mana means "any color or colorless" while 1 in rules text means "1 colorless" instead of "1 of any color or colorless". A new symbol for "1 colorless" would make sense and eliminate a confusing part of the game.
The open question is whether diamond is going to mean "1 colorless mana" or if it's a completely new kind of mana that has no color. I think the former is at least plausible. If it's not what happens, then diamond is going to be a crappy parastic mechanic like snow that shows up in one set and then disappears, and the price of Wastes a few years from now will be painfully high for a basic land simply for EDH demand.
"6th colour in that <> casting costs will require <> mana" That's what I've said several times now.
I think it's plausible that diamond is equivalent to 1 colorless, meaning Sol Ring says T: add diamond diamond. Doing so would not actually be anything new other than giving a symbol to "1 colorless mana", and getting rid of the confusing fact that {1} in a mana cost is absolutely not the same thing as {1} in rules text. The former is generic mana of any type and the latter is 1 colorless mana.
Also Vancouver mulligan with one free mulligan to 7 is official, so manabases might need to be changed accordingly.
Edit: Managed to get the text of the announcement.
The cutoff for the ability is at 3cmc, but the deck is built with a lot at 4CMC for fleshwrither/dimir house guard tutoring. I guess it's at least a free card, though, and would put lands onto the battlefield for free.
Cast LD, Cast Dualcaster, Dualcaster enters, copy LD, sac Dualcaster, and repeat to get infinite ETB/LTB effects (or as many as you want there to be, because you can halt it). Could win off of Gary ETBs, one sided board wipe off of Nevermaker/Venser, infinite mana from Phyrexian Altar. You could exile each opponent's grave off of Agent of Erebos so only you are left with a board.
We'll see, though. We did get new Drana last set, and she's a second lieutenant like Mikaeus is.
The fact that several cards that are in this deck are about to get errata to a new mana symbol is quite relevant. {C} mana costs could become relevant to the deck in the future. The fact that two discussions about the <> symbol have taken place so far, once when it was initially leaked and once when talking about filters, means that it's relevant to state plainly what the <> symbol is now that we know. It's not "future set discussion", it's discussing something that's of fundamental importance to EDH.
The only real difference is that Wastes doesn't have a type and therefore doesn't affect Domain. It's not a color so it doesn't affect Converge, either. This means that Command Tower (and everything else that says "any color") doesn't make {C}. It's a pseudo-color, only in the sense that it shows up in mana costs.
I don't think anything here precludes Wastes from having oracle text of "(tap for C)" like other basics do (ie. reminder text styled inside parentheses)".
https://twitter.com/TrickMTG/status/675303346681593856
If that Mystic Gate is real, then every colorless mana ability will produce <> (ie. Sol Ring will make <><>, Ancient Tomb will make <><> and shock you for it, Phyrexian Tower will make <>, Reflecting Pool makes it if you control a land that makes <>, Pain Lands make <>). It's not that the filter lands are the only ones that will do this.
The remaining question is whether colorless is a color or not, ie. whether Command Tower taps for WUBRGD or just WUBRG. Reflecting Pool would work regardless because it makes mana of "any type", not "any color".
It doesn't necessarily mean they're about to make a symbol to distinguish them, but it does acknowledge existing confusion.
Edit: MaRo in 2012: http://markrosewater.tumblr.com/post/26155270744/why-do-colored-mana-symbols-not-stack-like
"What if every colorless mana had its own symbol?"
The open question is whether diamond is going to mean "1 colorless mana" or if it's a completely new kind of mana that has no color. I think the former is at least plausible. If it's not what happens, then diamond is going to be a crappy parastic mechanic like snow that shows up in one set and then disappears, and the price of Wastes a few years from now will be painfully high for a basic land simply for EDH demand.
I think it's plausible that diamond is equivalent to 1 colorless, meaning Sol Ring says T: add diamond diamond. Doing so would not actually be anything new other than giving a symbol to "1 colorless mana", and getting rid of the confusing fact that {1} in a mana cost is absolutely not the same thing as {1} in rules text. The former is generic mana of any type and the latter is 1 colorless mana.