Turns out there are a lot of two-letter combinations in common parlance, where the second letter is a V, but I like the six that Mr. Deeney included in this puzzle. The revealer is simple brilliance, at 35A: Dubious food-eating guideline ... or a hint this puzzle's starred clues (FIVESECONDRULE). First, let's just acknowledge the selection of that excellent first word in the clue. Too funny! I also like the descriptor of "guideline," as if the FDA had put out a government-supported statement.
But the reinterpretation to mean that the rule guiding all the theme answers is that V comes in the second square is lovely. The only other answer that Mr. Deeney could have used is "UV rays." All other examples I can think of are three letter abbreviations, such as BVD, QVC, MVP. The theme answers are clued in a straightforward way, befitting a Wednesday. I like the trivia surrounding TVDINNER.
Some enjoyable fill include the wistful ICANDREAM. I've never listened to the entirety of Tristan and ISOLDE, but the Liebestod is an astounding piece of music.
I find it interesting how the theme answers drive unconventional choices in the fill. Because RVPARK starts with three consonants, you end up with DMVS (four consonants, no vowels) and ASP (two consonants, one vowel) in the region. Similarly with JVSQUAD, starting with four consonants: here we find JCREW and IQTEST.
Finally, a few fun clues to note:
10D: Bye at the French Open? (ADIEU)
19A: Only about one-sixth of these in humans is visible (EYES) - odd piece of trivia, but cool.
41A - (MINUS) - so much better than those puzzles where a continuation of an answer into another answer gets the same clue.
1D: You might be on it during a meeting (MUTE). As much as possible.