On the contrary, I think STVI is overrated. Why are the characters treated so badly? Kirk's suddenly a racist, McCoy is incompetent (no idea about Klingon anatomy?), Uhura can't speak Klingon (the communications officer doesn't know the language of the Federation's main rival?) and Spock mind rapes a screaming Valaris on the bridge while everyone just sits and watches.
And the less said about that Shakespeare-obsessed Chang, the better.
It could have been so much better with some rewrites.
I don't know? Kirk? Could being in the state of Cold War with an enemy and knowing that a member of said enemy murdered your son in cold blood have anything to do with it? Why does McCoy need to know the anatomy of the Klingons? We were still at a point where we didn't even know if there was one race that was considered Klingon or several. And Uhura was never shown as a linguist. That is a faulty assumption, she was always shown to be more of an engineer.
It seems that the reason some people don't like the movie is because the characters don't fit their personal assumptions about them. Just like the people that screamed bloody murder about T'Pol because Spock was supposedly the first Vulcan in Starfleet.