I think people tend to be WAY too lenient on the TOS movies. Nichols and Takei are awful in them (Though Koenig is weirdly great!) and the crew seem ridiculously lightweight and cosey compared to how they were in the series.
I do know what you mean.
I've never been able to associate Scotty in the movies with Scotty on TV for example. I know it's the same guy, being played by the same actor. But there's just something about 'Movie Scotty' (apart
from his weight!
) which doesn't seem to tally with the man who was the Enterprise's Mister Fix-It in the 1960s. Maybe it's because we never truly see him in the same kind of roles? Scotty was regularly put in command of the Enterprise on TV, quite apart from his engineering duties, but we never really saw that in a movie. The same is true of Takei and Nichols. Neither of the characters were ever what you could call 'utilized very strongly' on TV in the first place, but they were
strangely more dynamic all the same than they are in some of the films. There's a sort of lethargy to the performances of the wider TOS cast in the movies (maybe even with the Big Three).
Having said all that, there's a BIGGER lethargy in the Next Generation cast as seen in Nemesis
than there ever was in the TOS movie cast members. Having watched a bit of it recently, I have to say Stewarts', Frakes' and to a lesser extent Burton's performances were clearly just being phoned in (to me, Spiner and Sirtis did both at least seem to be making an effort).