The problem with that particular flavor of cerebral storytelling is that it often doesn't make for good movie making. Don't get me wrong, I'm all
for high-concept sci-fi, exploration of the unknown, but for every 2001, there's five of "Sphere" or "Mission to Mars." TMP lands somewhere in between. The parts where
it "explored the unknown" were alright, but then it went into "V'ger Existential Crisis" mode like it just read Nietzsche for the first time, and it was downhill from
Ultimately, I feel that style of storytelling is better suited for television. The characters should be the ultimate focus in a movie, and they weren't in TMP.
(More on topic, no, I don't think WoK is overrated.)
Although I don't agree, I guess that you're right as my taste, but first and foremost motivations tend to diverge to the point of being almost veritably unique, especially when it concerns cult films as well as even lesser known movies (adhering to movies that are even more rare and/or overlooked than the films you see being appreciated in different cult and nische groups).
After practically being born as a cinema buff having seen all the great classics of Kurosawa, Bergman, Hitchcock, Johm Ford, James Whale etc., the latest years I've discovered more and more what a weird (almost to cretinous levels) and abstract conceptualist I am, even in many areas outside of film. Antinomical to when I was 12-15, I've found myself overlooking or even caring very little for how character-driven something is nowadays. The importance of it depends on what kind of movie it is and what the ambitions or general idea of the creator seems to be. For me, opulent conceptuality can sometimes override and remunerate for a lot of other flaws in a film. In some movies, it's the only thing that matters. When I praise a Lucio Fulci film, I rarely praise the sometimes sleazy feel of the movies nor the zombies and the blood 'n' guts in his most famous films. For me, the most interesting aspect is the eye penetration and blinding as the most powerful of many symbols representing oppression which is the most central theme of L'aldila (The Beyond) or the stylish intro scene delineating death of art. Or the attack on catholicism in Beatrice Cenci and Non si sevizia un paperino which got him blacklisted.
And sometimes it's neither as "pretentious" or nebulous like those examples. Sometimes, the concept of Style-over-substance can be enough, meaning story being subdued for the film to only be meant as an visual experience of puissant cinematography. I don't really qualify that as exploitation, which I hate, because in exploitation there are no real concepts nor real ambitions in collation to many other films where there is traces of fat and limpid concepts no matter how single and uniformal they are.
Even though I hate inconsistencies in Star Trek (I thought pon farr
was something deeply private, Mr. Spock!), I think it's one of those culture phenomenons where in the end one of the biggest things about it is the rich conceptuality and prevalence of Hard Science Fiction. I think TMP were more successful in that area while WOK tend to be a more collatively straight-forward story. I also thought that the faster pace made it feel less like Star Trek and more like an epic war drama in space. I guess that basically, it comes down to which episodes I liked the most and what aspects of them and other episodes I appreciated the most.
Even though I love Khan, and the epic atmosphere, cinematography, direction and performances in WOK, I find that the purpose and background of Khan's activites to be too linear and straight-forward (damn how I hate to repeat that word, especially considering WOK is not at all so straight-forward compared to many modern blockbusters) to really be interesting in more ways than one. The basic plot is for me the biggest obstacle, even if the script and everything else is exceptionally good. Even if I still want Khan, I'd prefer another plot. And if I can't have Khan then I'd rather see a new Dr. Korby or Dr. Adams whose work has evolved to much greater extents than their predecessors' or the return of Charlie who's intent on claiming the world that rejected him and his superior powers as his own. I know everyone would hate these premises, but for me those themes feels more Star Trek to me than simply a baddie wanting to avenge the death of his love.
And like I said, I do not at all dislike Wrath of Khan. I just like TMP a little more and here I've tried to sum up why and explain that even though I like them almost equally, it is for totally different reasons. Wrath of Khan is easier to appreciate for the experience and adventure.
When I think about it you're probably right in that TPM would be better off as an episode.