I'm not sure I agree. TWOK was an explicit sequel to a TOS episode, unlike TMP. It certainly pissed the hell out of Roddenberry, but I'm not sure it was all that divisive within fandom.
Well, I didn't say it was. I just said it was a perfect example of the writers and producers saying (literally, this is documented) "we are going to make the film the way we want it, and we don't care what The Fans think...." and the result of that approach is that it's one of the most widely respected and appreciated elements of the entire franchise. So my point is that I believe it's better for the creators to create and let the chips fall where they may. Star Trek producers and studio executives too often go through a checklist of things they think the movie or show needs in order to be loved by fans. And, oftentimes, it shows...and not in a good way. The TNG movies are a perfect example.
But....to the point you are making...it was ABSOLUTELY divisive. There's practically an entire chapter in the Allan Asherman "Making of Star Trek II" book that outlines outrageous fan behavior in negative response to elements contained in the film, not the least of which were death threats levied at the production team if the "rumors about Spock's death are true." There are entire articles written by prominent fans in the "Best of Trek" publications that deride the film for all the same tired reasons you hear people moaning about these days (too much pew pew, Gene's Vision, not enough exploration, not thoughtful enough, etc etc etc). One article that has been burned into my memory was titled "Indiana Jones meets the Son of Skywalker" or some such drivel, and railed on the movie's action, use of the Enterprise as nothing more than a battleship, etc etc etc.