Stu...no. They cut way, way back on recurring characters last season, when they still had Jason, Fred and Bill in the cast. Last season they only had three real newbies in the cast and they did ~90% original sketches overall. They do need to work up recurring bits for the raft of new faces they brought in this season, but the trend goes back to last season.
I really don't think they retired J-Pop because Jason and Fred left. They were relatively minor characters for that bit, easily replaceable.