But seriously. This change HEAVILY nerfs raids that bring more of same-spec classes to a raid.
Since basically NOTHING stacks, it will be sub-optimal to bring 2 elemental shaman to a raid, or 2 BM hunters, etc...
What we'll see is that people will be forced to spec into disjunct trees that do stack:
1 BM hunter
1 MM hunter
1 Survival hunter
1 Elem sham
1 Enhance sham
1 Resto sham
1 Boomkin
1 Feral druid
1 Resto druid
.. and I thought Blizzard wanted to PREVENT forced talent specs.