World of Warcraft

Alterac Valley imbalance
We have discussed this numerous times. Based on the data we've collected over the years after all of the changes that have been made to Alterac Valley, we simply do not agree that there are any glaring imbalances in the map favoring one side over the other enough to easily sway a match one way or the other. (Source)

Masteries Cap
It's possible you will only get the benefit of the tree in which you've spent the most points, or will only get the benefit from say 50 points maximum with the bonus chosen from the tree with the most points in it. We'll have to see when the talent trees are more finalized and we start to figure out build strategies.

Overall, the goal is to spend points as you want, and not feel penalized for spending into another tree or feel like you have to game things by spending more points than you want in your tree. Remember these passive bonuses are designed to give you flexibility, not lock you into anything. (Source)

[...] Imagine you spend 55 points in Retribution, so you get the maximum passive talent tree bonuses from that tree. Your remaining points you can spend where you want, in Retribution, Protection or Holy. It does discourage some kind of true hybrid build where you go partway down multiple trees, but we aren't really trying to support those, and they aren't very popular today.

The flexibility comes (hopefully) in having more discretionary points that you can spend on talents you like, rather than sacrificing raw damage, healing or tanking to do so. (Source)

Mastery/Talent system and new players
It's designed partially with new players in mind. It will be much harder to have a truly terrible talent spec because you won't be able to help but be reasonably good at your chosen role.

The mastery stat itself won't show up until high level, and even when it does, you should have more confidence that it's a stat you want instead of say trying to figure out the percent of your damage that is physical damage to calculate if armor pen is good for you or not.

I admit that adding passive bonuses at all to talent trees complicates the talent feature slightly. We hope to make up for that by there being less paranoia about picking "the wrong" spec. The wrong spec might only be a slight loss instead of a tragic loss. As a point of comparison, dual-spec complicates talents a little, but overall we think it was good for the game. (Source)

Mastery bonus distribution
To answer your question — and this applies to all classes. the first two mastery stats are gained by placing points into a given talent tree (and wearing the gear intended for your class, e.g. leather for druids). This will allow us to remove many of the talents that always felt mandatory, especially at the min-max level, and allow room for customization.

When we begin revealing specific class information, (such as new spells and abilities, and the talent tree revamp) — the posts we've made thus far, will make much more sense. I feel, players should look at the stat/system changes, as well as this mastery post as a "piece of a puzzle" — and ask questions, provide feedback, but understand that until more information is released, it's not possible to see the whole of the picture. (Source)

Masteries Q&A
# 1. 28/28/20 spec. Does mastery on gear affect both highest trees or give no benefit at all?
Mastery on gear gives you one bonus. That bonus is the third passive (the unique one) in the tree in which you’ve spent the most points. In the examples we gave, those are Absorption, Radiance and Runic Power generation.

# 2. How are ferals and Dks as tanks working with mastery system in place? Are they to care about it for threat or do they have separate bonuses.
Ferals will have passive bonuses that say Cat: melee damage done, Bear: damage reduction. For death knights we have a different plan in mind that we’re not quite ready to discuss. DKs are undergoing some slight changes so they aren’t so GCD constrained and are less limited by rune cooldowns.

# 3. How are the non-pure classes going to be balanced against those with a full 76 point passive benefit? Balance, enhancement(not so much), shadow, feral, ele, resto, holy and Ret all have this issue.
Assume you only get the passive bonuses for the tree in which you’ve spent the most points, and there is a ceiling per tree (which could be something like 51-55 talent points). If you spend more points than that in a tree you still get the benefits of the talent. If you spend points in another tree, you are benefiting from those talents instead. Unless you try to make say a 40 / 36 / 0 build, you shouldn’t be losing passive bonuses.

If you turn level 10 and spend 1 point in Discipline, you are now a Disc priest. You receive the Disc talent tree passive bonuses and mastery rating on gear benefits your Disc passive bonus (Absorption). If you reach level 85 and have 70 points in Disc and 6 in Holy, you are still a Disc priest and the same rules apply. If you change your build to 51 Disc / 20 Holy / 5 Shadow, you are still a Disc priest.

# 4. Hybrids who use spells not improved by their spec on occasion such as heals or the extra lava burst are feeling that their non-specced spells are going to be extremely weak as compared to now.
They are weak now and the intent is to keep them that way. We aren’t trying to nerf them any more than they are today. If we want to make sure Resto shaman can do big Lava Bursts, we’ll give them a talent or something to make that happen. We don’t want Resto shaman to Lava Burst anywhere on the scale of an Elemental shaman. Again, how they perform today is pretty much the target for where we want to end up.

Death Knight (Forums / Talent Calculator)
Runic Power boost through Frost masteries
I know it's hard to get a feel for the design when you can't see the complete picture, but talent trees are changing for Cataclysm. As Eyonix referenced above, we are changing the DK rune mechanic a little so that you aren't so GCD constrained. This in turn will give us a chance to rebalance how much runic power Frost gets. Remember that in many cases we are pulling talents out of the trees and giving them to you as passive bonuses. In general if you see a passive talent tree bonus and think to yourself "Hmm, that doesn't sound very good for me," then it's probably because we haven't revealed the changes that lead to that being attractive to you. (Source)

Warrior (Forums / Talent Calculator)
Shockwave vs. Thunder Clap
Shockwave is technically a ranged attack, like a hunter shot. This means it's treated like an attack (and not a spell) for purposes of what you want but can't be dodged or parried. (I believe ranged attacks can be blocked, but I can't honestly remember off the top of my head.) The Shockwave treatment might be the right way to go for Thunder Clap. Thunder Clap is currently a spell that hits for physical damage and can't be dispelled. The distinction among spell, melee and ranged attack (or persistent auras like Consecrate) is a largely technical one that doesn't always encompass unusual abilities well.  (Source)

Thunder Clap in 3.3.3
I think we're likely to make Thunder Clap a ranged attack (like Shockwave) for 3.3.3. This will let it get 20…