There have also been heavy changes to how mastery works and what benefits you get from specializing in a talent tree. With the new system, you won't be seeing any bizarre talent specializations since there simply won't be any room for them; you'll level locked into one tree and won't see another until fairly late in the leveling process.
Zarhym - Cataclysm Class & Mastery Systems Update
The Rise of Specialization
We want to focus the talent trees towards your chosen style of gameplay right away. That first point you spend in a tree should be very meaningful. If you choose Enhancement, we want you to feel like an Enhancement shaman right away, not thirty talent points later. When talent trees are unlocked at level 10, you will be asked to choose your specialization (e.g. whether you want to be an Arms, Fury or Protection warrior) before spending that first point. Making this choice comes with certain benefits, including whatever passive bonuses you need to be effective in that role, and a signature ability that used to be buried deeper in the talent trees. These abilities and bonuses are only available by specializing in a specific tree. Each tree awards its own unique active ability and passives when chosen. The passive bonuses range from flat percentage increases, like a 20% increase to Fire damage for Fire mages or spell range increases for casters, to more interesting passives such as the passive rage regeneration of the former Anger Management talent for Arms warriors, Dual-Wield Specialization for Fury warriors and Combat rogues, or the ability to dual-wield itself for Enhancement shaman.
The initial talent tree selection unlocks active abilities that are core to the chosen role. Our goal is to choose abilities that let the specializations come into their own much earlier than was possible when a specialization-defining talent had to be buried deep enough that other talent trees couldn't access them. For example, having Lava Lash and Dual-Wield right away lets an Enhancement shaman feel like an Enhancement shaman. Other role-defining examples of abilities players can now get for free at level 10 include Mortal Strike, Bloodthirst, Shield Slam, Mutilate, Shadow Step, Thunderstorm, Earth Shield, Water Elemental, and Penance.
Does this mean that fury will be able to dual wield at level 10 rather than waiting for level 20? How many passive versus active abilities will the talent specialization grant? With talents like Anger Management gone and very few offspec talents left, one has to wonder about offspec tanking viability. Will crit immunity be built into specializing in the protection tree? Shield Slam as an ability gained via specializing takes away an ability that current off-spec tanks can use for tanking. Do we still even want them to tank, or is the design goal now that there will be protection-specced warriors (and paladins, and blood DKs, and feral druids) doing all the tanking from now on?
We don't know enough yet to really say with any certainty, but with Mortal Strike, Bloodthirst and Shield Slam listed as the active abilities core to each talent spec, it definitely seems like DPS-specced warriors will be losing enough tanking viability to make them performing in that role less viable. While they can certainly still strap on a shield (so far as we know, anyway -- for all I know, the ability to use a shield will be a specialization bonus), they're lacking Anger Management's threat increase to their bread-and-butter attacks and Shield Slam's big burst of threat.
Zarhym - Cataclysm Class & Mastery Systems Update
A True Mastery
The original passive Mastery bonuses players were to receive according to how they spent points in each tree are being replaced by the automatic passive bonuses earned when a tree specialization is chosen. These passives are flat percentages and we no longer intend for them to scale with the number of talent points spent. The Mastery bonus that was unique to each tree will now be derived from the Mastery stat, found on high-level items, and Mastery will be a passive skill learned from class trainers around level 75. In most cases, the Mastery stats will be the same as the tree-unique bonuses we announced earlier this year. These stats can be improved by stacking Mastery Rating found on high-level items.
So we have a pretty significant change to the mastery statistic
as well. To a certain degree, it's just a nomenclature change
... having those passive abilities as part of talent specialization instead of mastery. But we now still have the mastery stat and a trainable mastery skill with stackable mastery rating on gear. Mastery seems slated to work in combination with your talent specialization rather than simply with the tree you spent the most points in (since you'll be declaring a specialization rather than just speccing down a tree), but at this time, it does not appear that it will work mechanically differently. Vengeance
is moving to a passive protection bonus, apparently.
At this date, we don't have a lot more specific information to work with, but what we have is pretty astonishing. Talents will be far more important, point for point, in the new system because you'll have half as many points to work with. Your chosen tree isn't just meaningful or significant; it's of paramount importance, because you won't really be leveling with talents from any other tree. (To some degree respec and dual specialization will help out here ... One can only hope the price on both will come down.) Class-, role- or spec-defining abilities that are based on talents may become passive or active benefits of a talent tree specialization or may just be utterly gone. A lot of work remains before we know what we're getting, but this is major, and we'll pay close attention to it moving forward.