BM vs MM after KMST updates

But then you completely ignore pierce, which makes leveling easier in the first place.

That's true. I think the reason there isn't a lvl 200 MM is because they're just so rare at the moment. MM level faster than BM, but MM are just a lot rarer. Look at shadowers; we only have 1 lvl 200 and we're the 2nd fastest lvl'ing class.