Probably. It also lead to the monotonous ''KirkSpockandMcCoy'' no surprises-landing party week after week. Chekov and Scotty sometimes got a spot. The only time Uhura beamed down in Year THREE was by Parmen's force in PLATO'S STEPCHILDREN. Sulu got one final voyage with THAT WHICH SURVIVES. Chapel also got PLATO'S and briefly came down in PARADISE SYNDROME. Too much information...
Yeah I definitely got bored with landing parties in season 3. They should have mixed them up more.