I have defended TMP here a lot and this post made me smile. The movie is Trek's epic and I would take it over the shallow Abrahms nonsense we get now any day of the week. It is a grand, sprawling, intelligent adventure that is shot beautifully.
My only possible reply to that - unfortunately - is to quote the last line of dialogue in the TV series: "If only... If only... "
As a theatrical experience, however, it was still enough for me to want to see it twice. I recall the overture, as well as the entirely black background of both the overture and the opening credits.
Someone mentioned the use of an overture in 2001. I don't recall this from theatrical showings in the 1960s. However, I've seen it with the overture - a few minutes of Ligeti's "Atmospheres" - twice: during the national tour of a restored 70mm print in 2001, and a few years ago at AFI. If it's a latter-day addition, it's not a bad one. (Somewhere I have The Making of Kubrick's 2001 - a mass market 1970 paperback that's apparently rare these days - and that book probably has the answer.)