After giving us a rundown of the new Mastery system planned for Cataclysm, World of Warcraft developers answered a few burning questions that players had asked. Naturally, most people seem to be worried about what this means for hybrid classes.

"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."

As they've said before, Mastery bonuses on gear won't be retroactive on current level 80 gear, except type bonuses. So, we'll assume this is for level 80+ gear.

"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."

It has been noted that the details of Mastery so far seem to neglect Death Knights somewhat; or at least, it doesn't seem to mesh quite properly with their intricate tanking structure. Cataclysm Death Knights are going to be "less limited by rune cooldowns"? Interesting.

"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."

Ah, the big questions. Since Mastery grants bonuses for staying within your class's natural abilities, many are worried that it will suck the diversity out of the game. Blizzard's response seems to indicate that varied classes are still going to be useful, but ultimately, they WILL be weaker - but, in their view, it's not that big of a change. The last part, however, makes it seem like they're willing to tinker with the balance a little. We'll keep you up to date on the rest of Cataclysm's changes as they come!