i was playing w101 a couple of days ago and i am suprised how short mooshu is (3-4 bosses). I was expecting more of a challenge, but then how i realized how it was so short; i was mad. if you could make a few more quests in it, that would be splended. :)
It has way more then just 4 bosses, plus it does have lots of side quests. It's got several dungeons plus the jade oni that you can fight over and over again. Sounds like you were over leveled and just soloed your way through everything.
Because Marleybone was so long, Mooshu helps fix the level imbalance by implementing a rapid increase of difficulty so that if you were over leveled to begin with, you definitely weren't by the end of it.