I think the problem with Steve is that he was mainly there so that Marten would have somebody to complain to about his love life. When Marten started dating Dora and being all happy and shit, Steve became superfluous.
I'd guess that J.J. figured that the Steve/Meena plot really had nowhere else to go, which is why we hadn't seen him in so long. Now Meena's been written out, Steve is available again for wacky hijinks. (Too bad; I liked Meena. Favorite line: "The weird part is that I found two watches.")
Or maybe Steve is making a comeback because Marten is about to experience Major Girl-Drama and will soon need a sounding board.