I’m not sure how closely you’ve read, but sveeral classes are getting huge overhauls. Hunters will now use Energy (similar to Rogue’s Focus) and lose Mana entirely.
Warlocks will have Soul Shards as special resources like Runes, but they act to boost your spells in different ways (like making a spell instant or much mroe effective). Using them properly will be a challenge.
Every class is getting a major overhaul to talents, so that players will no longer be spending points to buy up passive bonuses. Instead, you get those naturally by picking combinations of talents or something. The Dev’s explained that this was because they realized everyone was more or elss forced to buy up lots and lots of passive bonuses.
Many fo the new Race/Class combinations will also affect gameplay a lot for people who choose them.
On top of this, there is of course the attributes shifting. Frankly, with all of these changes, it’s going to play very differently, and probably vastly for the better.
Honestly, that’s a huge cload of stuff which affect classes. Even leaving aside the direct impact stuff, they’re really improving the fundamental game. What more do you really want?