The appeal of musou gameplay has never been killing a million dudes for me, though it's certainly nice. They're just there to built meter for what I'm really supposed to be doing; criss-crossing the battlefield completing objectives, dealing with unexpected complications, and putting out fires (sometimes literally, freaking Wu.) It's what makes a musou game you want to replay. You don't just want to win a battle, you want to figure out how to win that battle perfectly.