I'm always surprised how much flavor they manage to fit into mechanics. Emrakrul comes down and your opponent goes temporarily insane, suiciding creatures into Emrakrul, using their own kill spells on their creatures, failing to find, etc. Then they snap out of it, and have a chance to pick up the pieces. But it may already be too late.
Obviously, we won't be able to make informed guesses until the rest of the set is spoiled, but I wouldn't be surprised if Emrakrul sees play in standard. Seems like it'd be a turn 7 ish play in a Rites, Delerium, or Ramp deck. It's clearly meant to go with Nahiri so maybe there's a Nahiri deck for it too, though not getting the cast trigger sucks. With the Eldrazi wish card they just spoiled I expect there will be more cards that work with the Eldrazi, and due to the collection numbers there should be at least 5 more colorless non-artifact cards.
The legendary werewolf is a huge disappointment. It doesn't seem like it'll be standard playable (compare it to Avacyn, Dankdwellers, etc.) or EDH playable.