Add to that BOTH Shatner and Nimoy thought Star Trek typecast them (Hell, Shatner was reduced to living in a Truck an d doing anything he could find be it a commercial or narrating 16mm film documentaries sold to public schools); and had a negative overall effect on their acting careers. Shatner was doing it for the paycheck and not because he liked the show or the character much
I don't agree really. "Star Trek" was his show. It was centered around his character and he got to be the lead for three seasons. He may not have liked having his career stalled afterward, but the series was one he enjoyed doing. Nimoy had issues, but Shatner was the BMOC and other than his competition with Nimoy, for a guy like Shatner, Trek was a dream job. Weekly heroics and romance. Why not come back and do it again? He was on board for the Phase II proposed relaunch and then the films.
I've never read anything by Shatner saying he was doing the Trek films "for the paycheck." Granted, as an actor, that's why you work - to make a living like anyone else. Actors who resent being typecast in a particular role don't generally jump back into the same role ten or more years later just when they're living it down. Shatner was getting more substantial roles by the time TMP loomed. As TWOK wrapped, "T.J. Hooker" was in production and premiered before Khan hit theaters. "Hooker" was a hit for him and Shatner was on his way back without Star Trek II. And he DID enjoy the script once Meyer came in and this was his chance to again headline a big event picture. At no time have I read that he resented the role. No actor wants his career stalled over one role, but his lean years were ending and I'm sure Star Trek's return in 1979 was a big part of that. He's had a great career ever since.
and Nimoy TURNED DOWN the opportunity to reprise the role of Spock in ST:TMP,
Yes, primarily because Paramount was holding out in royalty payments for using his image. Once Paramount settled, Nimoy joined the cast for TMP. He wasn't happy with the script, but that didn't stop him from joining up. He didn't resent the series either, but he didn't like the third year, mostly because Freiberger wouldn't recognize him as a lead of equal stature with Shatner and didn't listen to his suggestions. Nimoy actually was protective of "the Spock character" (as he termed him) and didn't want him used simply as a catchphrase spewing sidekick.
Nimoy was eventually talked/lured back into doing it was was the reason Spock was being killed off in STII (IE He requested it because he wanted to be done with the role.)
Nope, he didn't request it, Harve Bennett suggested it to him to pique his interest. Because Nimoy had such a rotten time on TMP, he chose to stay out of TWOK until Bennett gave him something interesting to chew on - "a great death scene." Nimoy didn't want Spock to be "just there." He wanted the character to do something and retain his dignity. This isn't a guy who resented the series or hated the role: he just wanted the be challenged as an actor and to have the character treated with respect.
They got him to agree to come back for STIII:TSFS only by givingh him the opportunity to direct it; and if he didn't - they were going to bring in another adult actor top play Spock and blame the 'change' on the Genesis effect.
I'm not sure where you're getting this stuff, but everything I've read says Nimoy wanted to come back because he had such a wonderful time on TWOK. And then since he knew he had the upper hand, he said he'd come back if he could direct. Michael Eisner agreed but then changed his mind because Eisner thought Nimoy demanded Spock be killed because he hated Star Trek. Nimoy assured him that no such clause was in his contract. After that was cleared up, Nimoy was back on the job. No other actor was going to replace him as Spock. Saavik was created to take over, but then Nimoy came back and they let her fade away.
Everytime the got together to do a ST film, they thought it would be the last one. All the "we had a great time..." and "The crew is like family..." was part of the Star Trek marketing machine because that's how GR talked about Star Trek after the series ended (although it wasn't something the 'Fab 4' promulgated on the convention circuit prior to the films); and the Star Trek fans ate that up.
Well, yes, they all thought each film was the last but only because they didn't seem to think they were making a franchise. They just thought they were doing "one last film." But then the box office would come in and Paramount would say "let's do another."
I'm sure some of the cast were like family. Some weren't. But that was indeed played up. I also feel some of the crap has been played up to sell books, too.