Or in TBC for that matter.
You can create a perfectly balanced raid composition with 25-man roster in TBC and in Wrath. But you can’t really stack dps and giga-blast through raids with extra dps that are just in there to pump.
The fun of Classic really was in melee stacked comps and crushing the raids due to (frankly, overpowered) way-too-many warriors and to some extent, rogues.
And you could also mostly maintain a balanced comp then too.
But in A 25-man roster, there isnt room to have a few more blasting dps in there.
Would be quite fun to tweak the bosses and trash a bit on health pools and see what a 30-man roster could do in woTLK. Add in 5 more warlocks? Go for it. 5 more DKs’s? Time to melee blast. Little mix of both? Who knows!
Let,s not go overboard with 40-man rosters which can be quite difficult to maintain logistically. But 5 more than 25. Manageable.