Continuity errors? Blame it on the director.
Maybe I missed it, but I've never seen anyone blame Nimoy for the problems with ST3.
Everyone and his dog blames Shatner for ST5, but it seems that no one wants to stick Nimoy with that kind of stigma.
Totally different. Nobody was coming down on Shatner for allowing continuity errors to slip into the final edit. Shatner caught hell for making what was considered by most people to be a crappy film (although I like it).
Neither of the Nimoy directed films were considered failures in the least. STIII was considered a rousing success when it premiered. I still have the print reviews.