Although debuff slots has been raised to 40, in a 25 man, you can only have like 1.6 or so debuff from each. Bring along 4 affliction locks and half of your debuff slots could easily be filled. So do you prioritise on who can use what debuffs?

And does anyone know how the debuffs are knocked off? I know those which share the same "rank" work in a FIFO way but some debuffs never get knocked off e.g. Hunter's Mark. Anyone has a clear concise way of explaining this?

Heh, no matter what, hunters shouldnt be using serpent sting in a 25 man raid. Unless of course only half the raid is still standing :b

Umm... itu scorpid sting, not serpent sting.