The bit about Scotty being fired was pretty good gallows humor. It was clear that failure meant death anyway, so being fired would be trivial by comparison, and thus the joke.
I'm sure James Doohan would have agreed that "The Apple" and "Friday's Child" were great episodes for Scotty. He got a lot of dialogue, and didn't get flung through the air for trying to help a girl, like he did in "The Changeling" and "Who Mourns for Adonais" and "The Lights of Zetar."
Scotty gave up on women after that-- while he could still walk.