I've spent quite a bit of time going over each class, and spec trying to find all the viable builds, and compare their merits. I've used recount, and number crunches to find the best healers, damage dealers, and done various duels and 2v2 PvP to pick out what classes worked and what didn't. I also noticed some bugs, so sit back and take a bit of a read.
One thing I noticed for pretty much all classes were a horrible abundance of talents that rely in critting. The thing is most classes walk around with 5%-9% crit making choosing almost any of these abilities mathematically terrible. Only classes that have Agility as their main stat might think about them with anywhere from 12%-17% crit, but it's still usually not a good option.
Additionally having 11 talent points, while the Tier 3 talents require exactly 11 points leads to many classes that have a critical talent in the Tier 1 section (Most every caster has a 50% mana regen while casting talent) of a particular tree meaning you either go that tree that has a critical tier 1 talent, or you miss out on your Tier 3 talent. I know the heavy investment to get your Tier 3 talents sounds engaging, but when I do decide to get a Tier 3 talent I feel like I'm scraping the bottom of that barrel for decent talents with not many choices. To rephrase: A hybrid build has 12 talents in Tier 1 to pick from, and potentially a select number of Tier 2 talents leading to 24 talents to consider. A build that gets the Tier 3 talent has 10 options to choose from, and you find yourself begrudgingly placing points into do-nothing talents just to get some hopefully OP Tier 3 skill.
If Tier 3 talents were locked to only one choice some other way, and 3-5 more talent points were added you'd have 10 points in your main tree to consider with 8 other Tier 1 talents to potentially pick up too, leading to more choice.
Warrior
Very lackluster, even with bugged abilities (Deep Wounds, and Flurry proccing on all attacks) it does mediocre damage. Your only real damaging attacks are Rend, Thunder Clap (mostly for out-of-range application of Deep Wounds, which is mostly just a bug), and Overpower. I tried two hand builds, dual wield builds, but they were both a wash. I noticed that each tree was missing their core attacks. If Warriors had access to Bloodthirst, Mortal Strike, or Shield Slam it would go a long way. It's very important to note that this class is not on par with others even with it's bugged abilities, a substantial buff would be desired.
Paladin
This is a good class. It does good damage, can wear mail, buff other people, and heal. It has limited mana though so making a pure healer is not ideal, but they're nice all around.
Warlock
This was a less impressive class. It does mediocre damage as either Affliction, Demonology, or Destruction. It has some nice tools through Fear, Succubus, and Fel Hunter, but once someone is on you it's difficult to survive.
Druid
This was a mixed bag. I felt like most classes were either good or bad, but this one made for a good healer. You can have very good mana regen through Dreamstate, and Intensity, but with Innervate it's a bit overkill. You can shapeshift around and annoyingly apply HoTs and DoTs while running away in Travel Form, and do good work. Straight up Feral however is mediocre. The damage is low, and you aren't playing to the good healing of the class. Same goes for Balance DPS. I think it's actually a good spec for PvP healers as you get Insect Swarm, and Treants (Which are noted to be broken right now), but you don't get the tools to deal actual good damage.
Mage
Not impressed with any of their specs. Their damage is low, most classes can get around their ability to kite, naturally they're unable to heal. I think if they had the option to Ice Block they'd be a bit better, you find youself dead with your Blink on cooldown usually, and this would let them reset the cooldown for their mobility/CC tools.
Hunter
A great class. It has good damage, and kiting potential, and can use it's pet to initiate fights from extreme distance.
Priest
Another mixed bag class. It has nice healing efficiency with Flash Heal, and various mana regen abilities. It has limited potential to increase it's DPS as any spec however, leading to DPS totals that don't shift much from 0 talent points. I find that most good classes have use for their points, and other classes struggle to find anything of use. It can play the same kind of game a Druid healer can by DoTing, and HoTing/Applying shields. I'd judge it worse overall than the Druid, but not by too much, could use a boost.
Shaman
This class feels like a worse Paladin. Enhancement can do some okay damage using Frost Shock trinket (which does not cause other Shocks to go on cooldown, while your other shocks do cause Frost Shock trinket to go on cooldown) (If this is fixed it would just leave a greater want for a buff), and either melee DPSing as either Duel Wield, or 2H, but it has less damage, less healing, less CC than your average Paladin.
Rogue
I'd say this is one of the worst classes. The damage is low, and there is no ability to heal. It feels like the same problem mages have where bad damage, and okay CC isn't enough. If powerful enough poisons were implemented it'd be a simple solution to the damage problem.
Death Knight
Even after the nerfs the DK is solid. It has great damage, and great CC, like a more aggressive Paladin.
I know that it can be at times difficult to really believe a list of classes with simple 'It's shit', or 'It's good', but for the most part the classes I noted as good had multiple players using to good effect, and the classes I noted as bad typically had a lot of unsatisfied players rerolling to something better. There might be some potential builds I missed, but I did my best not to skip out on anything, hybrid or not.
As a bonus are just a small number of objective issues I noticed:
Alliance mall has no ammo, and Horde mall has no Soul Shards.
Balance Tree has Eclipse, but druids can't get Starfire.
Rogue's Assassination tree has Deadly Brew even though rogues can't get any types of poisons at level 19.
My Human Male Hunter had no Gun skill.
My Human Male Druid had no One Handed Mace skill.
I hope this helped get a sense of how, at least I, view the classes currently.
