Better players = a better comp for the majority of the raiding community.
If you are world top X%, your player base may be good enough that you can class stack or pick and choose for variety but otherwise, get the best tank/heal/melee/ranged distribution you can with your best players and call it a day.
My general assumption (I've always raided 10m but going 25m for MoP) which may be wrong has been
12 ranged with one having a healing OS.
Then try to have a bench built that covers any role missing on a given week.
I'll be watching feedback on this thread as well. I'm operating a bit on 10m and assumptions atm concerning 25s.
@Bunjo: The best raid comp is 24 of my best friends with just enough tanks and just enough healers to clear instances, which is what most people here will tell you. There is no "ideal" class setup, just get all the buffs and a class mix for cooldowns and you should have more than enough. Also bumping is frowned upon, if nobody has anything useful to add to a topic ("perfect" raid setups rarely are useful), then it should drop off of the first page naturally.
please refrain from bumping threads, seeing as how this was still on the first page, there was zero reason to even do so, but it is against the rules. if you have something new to add to the thread, sure, but a simple 'yeah?' or 'bump' is not allowed. thank you.