Between the Shaman portion of the Class Panel and the Q&A session at WWI08, raiders have some great news (in my opinion). If you're a reader of Hybrid Theory, a few weeks back I discussed the possibility (and necessity) of certain group buffs becoming raid buffs. The devs have confirmed that yes, many of these things are becoming raid buffs.
The examples given were Totems and Unleashed Rage from Shaman, and Battle Shout for Warriors. This will greatly lower the need to stack Shaman so every single party of your raid has totems, but there's still the Bloodlust/Heroism issue. Taking 4-6 Shaman for Heroism is the single largest buff to your DPS that you can supply, so we'll see what happens. Either way, this is fantastic news, and something that has been sorely needed. Figuring out class balance for a raid can be fun, but not when your determining factor over who gets cut is "who won't fit in the Windfury group?"