I do wonder a bit though. He's got one slight point, even though it may be unintended. With Dualspeccs, you'll find that Hybrids like Paladins and so on will be far more powerful in a raidgroup than core classes like Rogues. We got the choice between DPS or DPS, or possibly DPS and PvP DPS. A Paladin though, got the choice between DPS or Healing/Tanking, or Tanking and Healing, whatever. Similar for Druids and Shamans, if they can keep their gearsets up to date.
Why should a Raidgroup bother with skilled core classes for one role, when they can have skilled hybrid classes for several roles?
Now, I'm not saying these changes are necessarily bad. It somewhat scares me that Pure DPS classes can be beaten on damage by a Hybrid that's running that particular raid as DPS even though he's primarily a tank or whatever. It makes me wonder if the core classes are really needed. Slimming down a raidgroup by upping the number of Hybrids is definitely a valid choice for a raidleader that wants to reduce the amount of idle players in a raidgroup.
I'm not too worried. I'm still one of the best my Guild can get their hands on, and I have no fear of being dislodged in favor of anyone else. I'm just pointing out possible future pit-traps the unwary can stumble upon. I am however interested in hearing what others think of the Hybrids vs Cores. (No Theo, you don't get to say anything, you are playing an Emodin)