Mozex

There is no way to give a creature infect in the current standard (RTR/Theros/M14).

Sorry, I hate ruining balance too :-)

Nice combo there.
I think some cheap scry burn spells would probably be better than steam augury and signal the clans.

PS, If you turn a keyrune into a creature it can still be tapped for mana.

I feel like 4 Nykthos is too many, you don't really want it until your third or fourth turn and you only want one. I'd cut that to 3.

I can't help but want at least one Borborygmos Enraged or Worldspine Wurm in here just so you can cheat it in with Garruk's -3.

Nice deck.
I think Titan's Strength might be better than Thunder Strike. The scry is decent for getting your next sorcery and it's a bit more damage to a player.
Another alternative would be Lightning Strike which is also more damage to a player, and can take out a blocker before you attack.

Ashiok provides you with two potential win conditions, Mill (great in a control mirror) and a source of creatures (okay in an aggro match). It also costs one less than Ral and is guaranteed to do something useful every turn.

I feel like Ashiok would be a far better planeswalker here than Ral. And you definitely want a 4th Thoughtseize so I'd drop a Stormbreath Dragon or Desecration Demon.

It doesn't work. You can only get a heroic trigger from casting a spell so to get infinite heroic triggers you have to cast infinite spells.

I'd do:
-3 Essence Backlash
+3 Izzet Charm (Good synergy will Chimera and allows you to counter non-creature spells)

I'd run Dryad Millitant over Favored Hoplite or Soldier of the Pantheon but probably leave Soldier in the sideboard.

Burnished Hart is good. Verdant Haven is also very good with Voyaging Satyr.

I like the themes in this deck. Boros Reckoner might be a bit difficult to cast reliably on turn three and it doesn't really fit the life gain/drain themes, so I'd put that up high on the cutting block. It also might be good for you to have a way to deal with an opponent's Erebos somewhere in your sideboard.

I'd definitely main-deck Aetherling or some other win condition (mill?). If your opponent has a decent amount of kill or a single Slaughter Games they can easily prevent you from winning.

Reverberate costs one less and is more effective since a single counter spell would only stop half of the damage.

For the moment you can still fling Malignus. At that point a reverb or a curse is enough for a kill regardless of how much life your opponent is sitting at.

I wouldn't use four Maze's End. Cut it down to two or three copies. After you draw the first one the rest are typically going to be wasted.

You Delvers only have about a 1/3 chance of flipping. You might be better off replacing them, or a different creature, with Pillar of Flame.

I see lots of black in the sideboard but barely anything in the main deck. You could replace dreg mangler with deadbridge Goliath and disentomb with revive to cut out black. A more focused mana base usually helps things perform more consistently.

Looks like fun. My only thought for change would be oblivion ring instead of pacifism, but that does depend on your meta game.

I would remove 2x grounded from the sideboard and replace it with plummet and/or snare the skies.

17 lands seems a little short. I have a little experience with urban burgeoning and it would allow you to run fewer lands in a flash heavy deck, but only two seems like too few. I think the deck would be stronger if you took out the 2x forced adaptation and added the last two urban burgeonings.