After the drydock indulgence, the V'Ger shots get diminishing returns because the point's been made already. They don't contribute to the story, except to say that V'Ger is really big, intricate, and weird. That point could have been made more efficiently.
I've never felt that way. For one thing, it's a chance to sit back and listen to one of the finest musical scores in motion picture history without a lot of dialogue and sound effects getting in the way, and there's nothing wrong with that. For another, the V'Ger flyover features what are still some of the most amazing, beautiful, spectacular images I've ever seen on the screen, a real triumph of design and FX technology. It's the closest thing I've ever seen onscreen to the sense of wonder at superadvanced alien technology that you get from books like Rendezvous with Rama
I'd like to think that had he had more time in post, Wise could have gotten the pace that he wanted in TMP.
And that's exactly what happened with the Director's Edition DVD 22 years later, which was edited under Wise's supervision, or at least following his and Roddenberry's notes. The musical cues "The Cloud" and "V'Ger Flyover" were intentionally written to have repetitive phrases that could be easily trimmed down so that the scenes could be adjusted to the appropriate length, something the filmmakers had always intended to do but were unable to do when the locked-down release date forced them to send an unfinished version to theaters. For the DE, both the cloud and flyover sequences were trimmed by a minute or so apiece.