New show set in the same shared universe with guest appearance from old cast, **** yes.
Reboot / remake... **** no.
Imagine the former. It could be so good. Willow turning up all super powerful... Giles popping his cheeky face in for a gander... Poor old Nick Brendon laying off the sauce long enough to do a guest stint. Maybe even closure on wtf happened at the end of Angel.
It has an easy setup too, with how Buffy ended (loads of slayers being activated). Just have it be about how most slayers are off doing world saving stuff or tackling the problems in big cities, but this one is stuck at a school in a crappy "normal" small town with no other slayers anywhere nearby... And then it turns out the town is riddled with vampires. Buffy and Faith show up in the final couple of episodes of season one but then Newbie the Vampire Slayer sorts out the big bad and they're like "she is teh new chosen one of crappytown" and leave her to it.
Instant hit
.