Got a bfa alpha invite on my warrior account. played around with a few classes, BrM feels like shit at the moment, DH tank felt good and more fluid. they reverted the change that made spirit bomb replace soulcarver, so thats a bit of a pain but overall the reduction in buttons on the DH made it feel more manageable than on live where you have shear-->fracture-->soulcarver--->that other strike ability--->infernal strike--->fierybrand--->immolation aura--->demonspikes--->what ever sigils you are using-->spiritbomb-->whatever else you need to push and have to keep all that more or less flowing.
Warlock was pretty enjoyable, but i feel like they overloaded abilities in demo. you have a ton of cooldowns to manage that are all 10secs-3 min. off the top of my head you have nether portal (only use when you are about to dump soul stones), slash (pet ability that gives a soulstone on a 10 sec CD), demon commander (big aoe cooldown), bilescourge bombers (aoe ability), molten core (gives you 2 charges of an instant cast ability that generates soulstones 20-30ish sec cooldown), implosion (requires monitoring of your imps time remaining). on top of that your juggling hand of gul'dan for imp summoning (at 3 soulstones) and dreadstalkers (20 sec cooldown 2 soulstones) and managing your molten core procs which provide 2 soulstones per cast. it just seems like a lot of things to juggle, im sure with WA's itll be significantly easier but currently i was always missing pushing an ability and leaving cooldowns just kinda hanging.