WHM is definitely the meatiest as far as lore goes. Healing trees has never been so badass (hence why I call it WHaM). I suppose it helps that having Raya and Ruhn as job trainers is pretty much the closest we'll ever get to learning directly from one of the city-state leaders. Only done ACN up to 50, but the Nymian stuff in the Scholar story is pretty cool, too. SMN feels kinda redundant to the MSQ as far as all the Allag and Ascian references.

The rest that I've done have all been pretty good as stories, but lacking as far as overall lore development goes. The AST story definitely feels like Sharlayan could become the bad guy of a future expansion.