I think the 5th film has some of the best character scenes from any ST movie. Seeing Spock's pain about his dad feeling disappointed about him being so human. McCoy ending the life of his dad to spare him pain and Kirk refusing to let go of his pain.
Sadly it also has Spock having a half brother, going to the centre of the galaxy in hours and GOD storyline.
I agree with all the points in your first paragraph. For me though, it wasn't the half-brother and God storyline that bothered me...it was the "centre of the galaxy" part. And the kitschy comedy scenes (99th floor of the Enterprise, the Rocket Boots jokes, Scotty banging his head, etc.) I also didn't like how the effects were rendered--unlike previous movies, the ship's just seemed to "glow" in space.
The movie did have cool Trek stuff that we hadn't seen in previous movies like the Shuttlecraft and Kirk just being the Captain of the Enterprise.