For me Fire Emblem Warriors lost against Hyrule Warriors some appeal for the normal enemies all look alike. Do I have this time around the ones ion red uniforms or in violett or whatever? In Hyrule Warrios Gorons looked different than skeletons different than Hyrulian army different than Bokoblin and so on.
Also the bosses, the big monsters especially were much better in Hyrule Warriors. That has to do with the use of items to defeat them. In FE Warriors it was basically a mounted unit. It also seems easier, which might be subjective. Harder mode makes the enemies only harder to kill, not cleverer in taking the battlefield.
On the other hand the pair-up dynamic in FE Warriors was great.