Interesting article up on Noxxic previewing level 100 dps rankings.
http://www.noxxic.com/wow/wod-level-100-dps-preview
Monk and hunters look good across all difficulties, could be tempted to go unholy dk also looking at that table.
This is after the hotfixes that were applied specifically to nerf the massively overperforming level 90 specs.
When 6.0 went live, there was obviously massive disparity between some specs (fire mages, fury warriors, warlocks at the top; hunters dead at the bottom), but the actual tuning of the classes was relatively balanced for level 100. It wasn't perfect, and you still had certain people on the beta moaning that they weren't able to compete, but it was close to being right.
Despite how much of a joke mythic is right now, Blizzard seemed to care enough about the game feeling unfair for some players for a few weeks at 90 that they applied a round of massive nerfs to the strong classes and massive buffs to the weaker ones. This means now that everything looks more balanced in Siege of Orgrimmar than it did (though classes with great burst - that funnily enough includes fury warriors, fire mages, and warlocks - are still at the top because of the stupidly short fight times), but the way it scales at 100 is now a bit of a cluster
****, as those numbers display.
TL;DR - even this late in the balancing, do not take that chart as gospel
at all. Blizzard will continue balancing in WoD before they open the raids (and maybe after). Nobody needs to reroll or get in a rage because of what the numbers are currently showing.