Nighy wasn't a gimmicky cameo, he was an actor playing a part.
I mean, yeah, he was playing a part, but there might as well have been a giant neon sign above him saying, "HEY, IT'S BILL NIGHY! ISN'T IT COOL WE GOT BILL NIGHY TO BE IN THIS EPISODE? BY THE WAY, DID YOU NOTICE THIS CHARACTER IS PLAYED BY BILL NIGHY?"
Not sure what you're saying here. Sounds like you'e saying no one can give Bill Nighy, an actor, an acting job, without it being seen as a gimmick? So, where's he supposed to get acting gigs, if all acting gigs for Bill Nighy are a gimmick? Why isn't it a gimmick for every actor who is famous to be given an acting gig?
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?