At first, I thought the theme would be phrases or names that start with a single letter. Then when I hit 35A: Phrase on the back of a buck (EPLURIBUSUNUM) - great clue, by the way - and saw the repeated E, I knew where we were going. I liked it a whole bunch. I could complain about having AOSCOTT in the grid, because of the extraneous answer with initials to start, but it doesn't bother me.
I was going to say that the I of ILOVEPARIS is an outlier, but the E in the Latin phrase is likewise a standalone word. OHENRYTWIST was immediately understandable, although I've never heard of it referred to that way. There is also an O. Henry Prize, which would have fit in the same space. But I can see there would have been possibly insurmountable difficulties in filling in that corner.
I zipped through this puzzle, so I hardly noticed some good stuff. I like both KLEE and MIRO, and they're placed symmetrically to boot. MAESTRO is fun, and reminds me of Mozart In The Jungle (worth it just to watch Gael García Bernal, even if his attempts at conducting are laughable). ASTUTE reminds me of Paul Simon and "Diamonds on the Soles of Her Shoes".
MAGGOT is unpleasant.
1A: "Gotta run!" (IMOFF) - I know people come down on both sides of the debate on the use of colloquial exclamations, but I enjoy them. I give this a B+. I also want to add that I put CRass in at 14A: Potty-mouthed (CRUDE), and for a while was very pleased to notice that the word has "ass" in it, which seemed appropriate. Until it was wrong. Then I was no longer pleased. It's not nearly as much fun that the actual answer has "rude" in it. But that's me.
YIKES! It's the end of May. Let's all welcome Horace and Frannie back into the driver's seat for tomorrow.