On some level the movies all have to stand apart from the TV shows, and I find that fine and acceptable (after all, how do you appeal to the broad audience of movie-goers if you're tied into a television continuity they may never even have seen?), and Generations does seem to understand that it needed to be understandable to audiences moving directly to it from The Undiscovered Country, hence bridging the gap with the prologue on the Enterprise-B was a sound move. But, well, Treks II - VII have that narrative link, kind of, that one might expect from movie sequels, a cinematic, theatrical progression; but VIII, IX and X are basically all stand-alone stories. This coming from The Next Generation crew, which (on TV) had largely been praised for the way they hadn't been afraid to tackle character arcs and grow continuity across multiple episodes and seasons. The TNG movies feel risk-adverse. A little bit like how Voyager and Enterprise each felt increasingly risk adverse.
I agree with your earlier premise that the TOS movies really broke from the standard format, which made them feel far more like big, special events. I mean, for two of the six films, the crew is not even technically in Starfleet.
TMP never could have been a TOS episode, as it was largely built around the premise of the main characters rediscovering themselves and their relationships after significant time apart.
TWOK was all about consequences, death and mid-life...something the original show could never have done.
TSFS and TVH were completely out of the standard format.
It's really only the last two films that could have been done in the television format as episodes.
The TNG films were exactly the opposite. Maybe an argument could be made for GEN being different because the Enterprise gets destroyed and Shatner guest stars....but I think even that is a stretch, given that we had seen crossovers with the TOS characters already. For the most part, any of the TNG films could have been episodes...and that's exactly how they all felt.