Given the incompleteness of the trees I know that some of these issues may already be in the works for a change, but given the information we currently have I'm going to go ahead and outline the things I want to talk about as if these trees were permanent.
Spec favoritism in hybrid talent trees: I get that you want hybrid classes to branch into other roles for short periods of time on occasion, but the hybrid classes, particularly the shaman talent tree, have a severe shortage of talents that every spec would use regularly.
--In its current iteration the Shaman tree is disgusting, the entire thing might as well be a giant sign that says "Switch to Resto".
--For druids it very obviously favors feral and guardian. The only "hybrid" thing that would be good for a Balance is the healing = lunar/solar energy. All the other hybrid stuff heavily favors being in melee. Which a good boomkin will not be. Ever. Barring some kind of gimmick of course.
--I don't have a death knight but by looking at the talents they seem to very heavily favor PvP, they all feel like old school pvp talents, with the exception of the AoE ones, those are pretty cool!
--Same with Priests. Most of the talents, barring the health % ones, feel very pvp-ish. I do have to say the shadow vs healing seems pretty even, although the holy vs disc doesn't seem to be represented AT ALL in the talent trees. For all they are concerned Priests have 2 specs, healing and shadow.
--I don't particularly have much to complain about Paladins, to be perfectly honest if I was to list a benchmark for how you should balance all of the hybrid talent trees it would be the Paladins. It's very obvious that almost every single talent and talent tier was carefully thought about how it could be beneficial to all three specs of Paladin.
Another concern I have is that while some specs of some classes get very spec defining abilities at level 10, there are some that don't even get anything at level 10 due to making some abilities baseline. This needs to be fixed asap. Example: Go look at the beast mastery spec. They don't get anything to distinguish them as a "Beast Mastery Hunter" until level THIRTY.
Also, something else I noticed; if something is a spec defining level 10 ability, you're not afraid to put an important passive along with it at level 10, but if you learn something at later levels sometimes you have two paired abilities being learned at vastly different levels. Example: Elemental Shaman get rolling thunder, the ability that gives them extra Lightning Shield charges, at level 20; however, they don't get Fulmination, the ability that actually USES those extra charges, until level 30. These abilities should be at the same level, they shouldn't be at different levels simply for the fact that they used to be in different talent tiers. That just doesn't make sense under the new "get it when you need it" model.
That's all I can think of at the moment (and is plenty to mull over really). Thanks for putting these out so soon for us to maliciously rip apart over and over through the next few months!