So what classes are looking to be OP for season 3? DH like always?
Like dahbomb said, it's hard to tell simply because of the volume of changes as well as the fact that not many people tested the PTR after the last round of changes, all the bugfixes, and the resets. Barb and DH are looking very strong, but so are WD and Monk. I'd say crusaders are probably the worst off, but that's probably just a symptom of them having the smallest playerbase and the least amount of testers/theorycrafters.
Mannercookie did clear grift 59 with a new barb holy build (which is the one big outlier), but that was with close to perfect PTR gear, and he also abused a bug that allowed mirinae (smite gem) to proc a billion times. That will probably be fixed, but knowing blizzard, they'll slip in some stealth nerf first, then fix the bugs later lol.