i can tell you after playing mage right now our burst is pretty good, our conserve (call it what you might, sustained damage?) is lacking quite a bit, however with our 2cnd gold trait that might (will) help alot with that part. At least its fun to play.
Mages aren't at the top! /gasp Have we finally been removed from our throne!! I guess its true that no king rules forever. On a more serious note Demo locks seem to be killing it
http://www.furiouspaul.com/overwatch/ This website has alot guides if not all of them for each hero and map. Seems like it will become a useful resource soon. P.S. Gives a detailed breakdown on hero v hero situations