Moorwing filtered a lot of bosses because if you don't move the flea caravan, it blocks the entrance to Bellhart. That change makes sense imo.

You can enter Bellhart from the east by going up the worm ways which means Moorwing is optional even if you don't move the caravan.

I'm also not sure why they nerfed Sister Splinter. I'm more confused about the fact that they nerfed her but not the Last Judge. I've seen more people complain about the judge (due to the runback path) than sister splinter.