My only concern with this is how they are going to make this fair for 10 v 25 man raiding.
Since both 10 man and 25 man is the same set of achievment even if many feels there is a big diffrence between them and so on this will make the gap even bigger.
In a 10 man guild you will have players with this or that talent only.
but in the 25 man raid where you perhaps have 3 druids and 4 paladins you can take every single thing to help you in raids. which in my honest opinion is "Unfair" advantage.
i know the talents is yet set and the numbers and such will change but from this PoV that is now, the 25 man will basicly get boosted (sorry for bad choice of word) with all these abilitys that they can have due to the numbers.
I might be totally off right now but i just thought of in a 10 man v 25 man aspect with this on perhaps a bad way
Edit;this might also make guilds stack classes dumdumdum!