Botts had a hell of a job in front of him in Buffalo. The Pegulas never stopped meddling in shit, and are notorious for doing so. I've been a Bills fan my entire life, and watching them step on toes for that club until a couple years ago was awful. Coincidentally, once they got their noses out of the football side of things, the team started to turn around for the first time in 20+ years.
The Pegulas' constantly poking around in things, coupled with a dude who seems (rightfully so, arguably) constantly unhappy in Eichel, makes for a pretty bad situation for anyone. Not that I think Botterill is some kind of GM wunderkind, but I don't know that anyone else could've done more in that spot.
Anyway, bring him back. I don't see how anything negative could come from a guy with experience and familiarity with the club returning to be an assistant GM again.