except he's incredibly susceptible to cc - just like other "broken" characters like skarner, xin, garen, riven, singed, and the new jax. if he's on you, exhaust him. if he's on someone else, stun him and cremate him. his early game laning is tough, because he has no mana so it's easy to blow through it all and you have to be pretty passive early, and his jungling isn't super easy because he has no close the gap and often can't finish off champs solo before he gets items. he's really dangerous with a few kills...but that's just like everyone else.
kanthos - yi is pretty fun, especially AP yi (alpha strike and meditate ftw!) on dominion. as for burst casters like Annie, they're always really good at the lower levels where people don't know how to focus damage. once you've played a lot, you'll find that burst casters get focused down and busted up early, but a character like annie can still carry pretty easy.