Because of several and parallel related Trek Tech threads, I rewatched parts of ST III.
IMHO, the film is a mixed bag. - SPOILER / SPOILING ALERT
It has great VFX cinematography and the whole "Escape from Frisco" sequence is a ST milestone: fast paced, excellently edited with witty dialogue and memorable lines (which I like to quote up to this day). I never get tired of seeing it.
Where the film sucks is the entire Klingon storyline which has more plot holes than ST VI (which I nevertheless enjoy watching because it has many of the elements that made the "Escape from Frisco" sequence so great).
Their and in particular Kruge's portrayal was grotesque and goofy.
- He kills Valkris for no good reason, especially since she is apparently devoted and loyal to him.
- He kills his gunner for screwing up and almost shot Torg as if he had an abundance of crew members.
- He desperately wants to learn the secrets of Genesis but doesn't mind killing the very scientist who has the answers he's looking for (or is he really that stupid assuming that Kirk has all the answers?) - Kill first and ask questions later?
- He thinks he can take over a Federation starship with full crew with only a handful of people (who's piloting the Klingon Bird of Prey next?)
- And most of all: What did he actually expect Kirk to do when he ordered him several times "to hand over Genesis". Kirk didn't even flash a data device or anything like that as bait. Did Kruge expect Kirk to pull the Genesis Device out of his pocket Stanley Ipkiss (The Mask) style?!?
He could have learned a couple of lessons from Kirk's previous antagonist Khan: First let me see and evaluate the data and then I decide what to do next. As a follow-up antagonist the character of Kruge was a dismal failure, IMO.
And the whole thing with Spock's soul (despite many great moments revolving around "Dr. McSpock") was pitiful mumbojumbo. As an automaton repairing the Enterprise's
main energizer in ST II I would have bought the concept. But this Spock automaton apparently had empathy and memories which I think belongs to the soul. Better not to try to make sense of it and rather let it be forgotten.
And I almost forgot: So Dr. Carol Marcus, concerned about microscopic lifeforms in ST II, was essentially a fraud and the whole Genesis stuff was a hoax because they used unstable matter? Here the subsequent movie obviously created a twist at the expense of previously introduced characters and what the screenplay writers had tried to establish in ST II.
The film had good entertainment value, but nothing more and nothing less, IMHO.