Seems clear how it will be in pvp:
Ele / warrior: top tier
Guardian / Necro: high tier
Ranger / Thief: medium tier
Engineer / mesmer: low tier
1. Top end play won't have evolved until a few months after release once a large enough population is able to actually play the game.
2. Right now we have only seen an early beta build, much less a release build
Speculation about what will be in top end play at this point is just dumb.