Aside from get a good time slot and run five Roddenberry and Coon produced years, of course. 
For me, I wish they'd established the friendship between Scott and McCoy mentioned in the writer's guide. They were both hard-drinking, passionate pragmatists a decade or so Kirk's senior. It would have been cool if they hit the flesh pots on Wrigley's together, the one stinking of Oban and Laphroaig, the other of Maker's Mark and Woodford Reserve.
(The old salt Scotty drinking with the green Chekov in "Tribbles" is one of the most charming moments in all of Trek.)

For me, I wish they'd established the friendship between Scott and McCoy mentioned in the writer's guide. They were both hard-drinking, passionate pragmatists a decade or so Kirk's senior. It would have been cool if they hit the flesh pots on Wrigley's together, the one stinking of Oban and Laphroaig, the other of Maker's Mark and Woodford Reserve.
(The old salt Scotty drinking with the green Chekov in "Tribbles" is one of the most charming moments in all of Trek.)