Wow. I saw an entirely different movie. Loved it then, love it now. Watching when it first came out gives one a totally different experience than someone watching it years later after so much Star Trek has been produced. TSFS gave Trek tons of stuff that would carry through for decades.
For me, that last part is the biggest problem. SFS represents the ILMization of TREK, with big terrestrial-minded blimp hangars in space replacing spaceframes that looked like they belonged out there.
on TWOK, ILM, with the (admittedly remarkable) exceptions of the too-cool starfields and the Genesis tape, was basically just hired-hands executing the concepts of others (and in the case of the Genesis cave paintings, maybe distorting that concept, since instead of a ton of lava bubbles that burst you just have the one that they're standing in.) The creative input from ILM just makes SFS seem like EXPLORERS and the SW films in style.