ST:TNG probably has several unjumping moments. I’d also add “put collars on the uniforms” and “made Troi wear pants”
Actually, for ST:TNG, the moment was “Hiring Melinda Snodgrass.”
I’ll also point out that Sisko’s goatee heralded the moment that DS9 kicked itself into high
gear.  Not that it was bad before then, but the series kind of meandered around somewhat,
not sure of where it was going.
“Where are you from?”
“Omaha”
“That’s funny. We’ve got a city in Nebraska named Omaha”
Would “NOT hiring the McGinley” work?
For BtVS, “Getting rid of the Riley”