I did a shallow analysis of the commons and uncommons of Theros. Hope it's clear.
If you'd like more stats, let me know.
Average CMC creatures:
Number of commons using devotion: 3
Number of commons with heroic: 4
Number of commons with monstrous: 2
Unconditional removal: 2 (1 with attacking or blocking clause), W and B
Conditional 'removal' creatures:
W 1 Power 2 or less
U 2 Flash 3/2 and 2R sac for 2 dmg
B 4 -4/-4, -1/-1 aura, 2dmg to crt, death trigger -3/-3
R 4 5dmg divided, 3dmg, 4dmg, 1dmg
G 2 7dmg to flying,
Conditional removal enchantments:
W 1 Destroy enchant
R 1 3W sac destroy enchant
G 1 exile art or enchant
1W Battlewise Valor +2/+2
3W Divine Verdict Destroy attacker or blocker
W Gods Willing Protection
1W Last Breath Exile creature power 2 or less
2W Ray of Dissolution Destroy enchantment
3U Breaching Hippocamp 3/2 flash untaps another creature
3U Griptide Creature on top of library
U Lost in a Labyrinth -3/0
1U Voyage's End Bounce
B Boon of Erebos +2/0 Regen
4B Lash of the Whip -4/-4
BB Pharika's Cure 2dmg
6RR Boulderfall 5dmg divided
1R Lightning Strike 3dmg
R Spark Jolt 1dmg
R Titan's Strength +3/+1
1G Defend the Hearth Prevent dmg to players
2G Feral Invocation +2/+2 aura
1G Savage Surge +2/+2 untap
2G Shredding Winds 7dmg to creature with flying
Average CMC creatures:
Number of uncommons using devotion: 4
Number of uncommons with heroic: 7
Number of uncommons with monstrous: 4
Unconditional removal: none
Conditional 'removal' creatures:
W 2 Exile white perm, power 4 or greater
B 2 Destroy black crt, Monstrous keepsake gorgon
R 2 Magma Jet, Ordeal of purphoros
G 1 Hunt the Hunter (fight green crt)
Gold 2 Flash 3/2 flying, shipwreck singer
A 1 5, sac: bolt
2W Dauntless Onslaught Two creatures +2/+2
U Triton Tactics Two creatures 0/+3, untap, frost breath blocked creatures
3B Cutthroat Maneuver Two creatures +1/+1 lifelink
B Dark Betrayal Destroy black crt
R Coordinated Assault Two creatures +1/0 and first strike
1R Magma Jet 2dmg creature or player, scry 2
2G Artisan's Sorrow Destroy art/enchant, scry 2
G Warrior's Lesson Two creatures: curiosity
RG Destructive Revelry Destroy art/enchant, controller 2 dmg
2GU Horizon Chimera Flash, flying, trample, draw a card = gain 1 life
Thoughts so far:
At common, green's creatures are the biggest, with red coming second. W, U and B have way more toughness than power. This makes Theros seem like a slow format.
Devotion doesn't seem to be an actual strategy, due to lack of devotion cards (3@Common, 4@Uncommon).
The three common removal spells that can kill a Nessian asp by itself are Boulderfall (8), Divine Verdict (4) and Sip of Hemlock (6).
Enchantment removal is prevalent, but only in Green and White.
I'd say devotion is a strategy, but only for black, since it has 2 common devotion cards, one of which is pretty bomby, and a very bomby uncommon. (And if you play the prerelease, guaranteed devotion-related rare).
Generally, devotion doesn't seem to require much in the way of "strategy" since it just wants you to develop your board state anyway - especially since there aren't many sweepers anyway.
I've been studying the full spoiler since I saw it.. trying to decipher how this format will play out as best I can, what color I want to pick at the prerelease, etc.. and so far I have no god damned clue how it will play out.
The ONLY thing I'm 100% sure of, is that black is the worst 'splash' color of them all. The majority of it's good commons and uncommons all require BB to cast. Going mono-black doesn't seem worth the risk/reward, as it has some very janky points in its curve. If you have enough of the bombs, and a fair amount of the devotion cards, it could be pretty nuts, but that is unlikely to happen consistently.
So, therefore the main thing I've taken away at this point is that I'm avoiding black barring some crazy pool that is heavy black. In that case, I'll have wished I picked black as my promo pack. Maybe someone better at numbers can do the math to see if taking black for your promo pack makes going mono, or heavy, black a more likely scenario. I'd rather hedge my bets on opening relevant cards and go with one of the other 4 (leaning towards red or green at this point).
edit: Meant to clarify, when it comes time to start drafting this set, if you have people that read signals well then forcing black could be a legit strategy. For the random format that is sealed, however, I feel like this will bite you in the ass more then help you. That's one reason I'm leaning towards green, as it has the most color fixers to increase the chances I can play a bomb in another color that I open. Red because it's promo card is the easiest to play and red's aggressive curve could let it win a bunch of games against people that just build their deck wrong and get 'too slow' of a start. With all the bestow stuff available, it has good reach even when they start to stabilize as well.
Been playing on Cockatrice a little, so far only with Green, so some thoughts:
Green has a lot of acceleration. Between the land untapper at 2cc and the devotion mana generator at 4 cc, you can ramp pretty quickly.
Time to Feed is premium removal. It's so good, because green's men outsize everyone else much more efficiently. I didn't realize it when I read the spoiler, but its a spell that targets, so it triggers Heroic. With Staunch-Hearted Warrior, you can eat anything smaller than 4/4 and still be left with a 4/4 of your own.
Asp is ridiculous as expected, and instant enchantment removal can blow people out just by removing a key aura after blocks are declared.
Removal isn't hard to find, it's just very expensive. There's actually a glut of removal at 4-5-6. Enchantments don't actually matter; bestow is just a nice value generating mechanic. Ray of dissolution is certainly not maindeckable.
With 3 common, colorless manafixers there's actually plenty of mana fixing - but like the removal it comes at a price: traveler's amulet is the least bad. I did make a 5 color deck that was very fun and worked well. Though I suspect 2 color (sometimes with a 3rd splash as is common in limited) will as always be the norm. Devotion is an almost entirely irrelevant, incidental thing.
As you point out, the power/toughness ratio is quite low, but despite this I'm just not seeing board-stalls happening.
The format doesn't seem quite as slow as people thought it was going to be. It's decidedly mid-rangey, not super aggressive but if you don't curve out you can easily be punished - though I have a greedy tendency to eschew 2-drops when possible, so I may be biased. It's probably no more slow than RTR, DGM. There are some decidedly powerful interactions at common, but still a large amount of games I played were determined by bombs - the ratio of bombs to duds at rare and mythic is high.
Upon browsing the set, one thing I noticed that may sometimes be relevant is that there is almost no way to deal with hexproof. Like, at all. So Benthic Giant, even if he's a little slow, is almost impossible to remove. Unless I missed one, the only way to get rid of hexproof is with Elspeth's - (kills all 4 power or higher), Hythonia's monstrous (kills all non-gorgon), or Agent of the Fates (hoping they have to sac the hexproof dude). With that said, a monstous Fleecemane Lion can only be removed by Agent, so he's basically immortal.
So, if in a board stall, an aura-happy Benthic Giant (like with Aqueous Form) is serious trouble.
Drafted 5times on cockatrice so far: UW heroic, RU aggro, RB minotaurs, BU devotion, BU control
All the games I played weren't slow at all.
Blue is actually an extremely aggressive color in this format, with Vaporkin and the nymph.
Vaporkin is especially amazing. The only way for you to lose tempo to your opponent casting this card is if it gets Jolted. Otherwise, you keep munching away your opponent's life until he can stop it at (usually) around 5mana.
As for more control-oriented black builds, the devotion drainer is definitely the keycard. The general plan is to stop the early aggression with Phalanx/Kiss, gain card advantage with Disciple/Read the Bones, then win the life race with the devotion drainer.
Welkin Tern is back... and with it, Zendikar-esque speeds...
Maybe not quite, but I agree that blue is looking pretty aggressive in here. They also switched the P/T on Nephalia Seakite which is no small change in the swing of things. I think as far as creature quality goes, blue might actually be better here than in M14. The thing blue lacks here though is the absurd amount of removal that blue has in M14. So, overall, probably going to be weaker, (how could it not be?) but it will have a pretty nice, aggressive gameplan. Some of its ground butts are pretty nice too.