I don't particularly like putting 6+ stack hordes through the salami slicer, although you could argue that at least is decisive.

I would say one full stack battle per province captured would be about right.

That said, I do tend to play RTW on very hard because then at least the AI will tend to have full stacks, even if they often have multiple ones. I don't like fighting small battles that favour me. I don't mind the VH campaign setting of RTW.

I found the late game Shogun battles could often get too large and repetitive (Hojo horde). MTW was ok, IIRC, if you did not have to conquer the world (GA game).