I'll be glad to admit that of the original six Trek movies, Trek V is perhaps my second or third favorite.
There was something about Trek V that "felt" like I was watching the Trek of my youth. The movie felt like a lost episode, unlike any of the other films with the original cast.
All the other movies felt too self contained and didn't have that sense of venturing out into the universe to discover "strange new worlds". IMHO, Trek V had that sense of exploration and adventure missing in the other films.
Don't get me wrong, I love all the Trek films EXCEPT for Trek 6 which I've never warmed up to. Trek V presented the heroic characters I remember from the TV show. In Trek 6, these heroic characters suddenly are just so damned grumpy. Everyone hates the Klingons, there are large clocks on the bridge (which were never there before) to remind everyone of the time and Spock mind-rapes his colleague because the crew needs information to save the day. That scene alone is so unpleasant to watch that I'd rather not watch the whole film just to avoid it.
Yes, there's much to dislike about Trek V as well. It's certainly not a great film but I think it's great Star Trek. Much of the humor doesn't work. Characters do incredibly embarrassing things (Uhura's fan dance and Scotty bumping his head don't do these characters any justice).
I know it's been done in fan edits but there's a great movie there despite the silliness that exists in the version released to theaters.