The Undiscovered Country
is one of my favorite Trek films. A fitting send-off for the TOS gang.
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.
All valid points regarding the characters in TUC.