^Interestingly, nearly half of those were eventually used for one thing or another.
That did occur to me. Originality is not my strong point, though I still think that they would work for TMP.
Given the marketing concerns discussed above, the need to make it clear that this was a movie and not a TV show (since, remember, there had already been two Trek TV series by this point, including the animated one), I think they chose the right title. The Motion Picture is classier than The Movie would've been, conveying the sense of sophistication they were going for. In Thy Image or The Human Adventure could've worked if it hadn't been the first-ever movie, but since it was, I can understand why the need to specify that took precedence.
Yeah, I take your point about forgoing In Thy Image or The Human Adventure. I just find the phrase 'The Motion Picture' somewhat pompous and needlessly wordy.
To be fair, I appreciate that it was a different era and the term 'motion picture' was more commonly used then than it is now. But...it just doesn't work for me.