How are we defining peak? If you do a search for class design you’ll find me repeatedly stating that MoP was the best Only thing trash about MoP is the shattering happened in Cata.
Wrath is great because it is a Pre-Shattering, Pre-CRZ, Pre-Scaling, Pre-Pruning, Pre-Flying War world.
Cata is great because it is a Pre-CRZ, Pre-Scaling, Pre-Pruning, Pre-Flying War world.
MoP is great because it is a Pre-Scaling, Pre-Pruning, Pre-Flying War world.
WoD is great because it is a Pre-Scaling world.
With Legion came scaling so no expansion after WoD will ever be better than any of the ones from WoD and earlier IN MY OPINION. I don’t care how many subscribers they have, an expac could bring Wow to 100m subscribers and it still wouldn’t be good as WoD and earlier gameplay.