In STII: TWOK, we see Chekov as First Officer of the Reliant but that's as far as his on-screen career went. Shouldn't he have gotten his own ship by the time of ST:VI or even Generations?
On the other hand, Sulu still seemed to be a helmsman in ST:V and then one movie later, he's Captain of the Excelsior. We never see him serve as First Officer, which would seem a logical step even if it wasn't required.
I wonder if the events of TWOK put a damper on Chekov's career path? Maybe he was indirectly blamed for some of the things that happened and kept getting put at the end of the promotion queue.