I think its a bit unfair to say he is becoming a joke character, yeah the Jimmy thing was strange. However the rest of the episode was great, Ross was funny and he kept true to his bad boy ways by messing with the minibus. My personal theory is that Ian doesnt want to give him a big storyline yet because Michael has to leave for a few months to climb Everest. I think when he returns to full time filming he will get a big storyline. We just have to be patient.