Maybe I'm just a BIGAPE, but I thought today's theme lacked afflatus. Circled letters - not a favorite of mine - appear in sets of one to five within larger words across the grid. The circled letters "evolve" from the D within TENACIOUSD to the full word DARWIN (Evolution theorist ... or what the circled letters are evolving toward). The evolution is not completely linear; read left to right and top to bottom, it starts with D then goes to DA then DAN, then DARN to DARIN to DARWIN - just like in real human evolution.
I wondered if 14A: Skills (CRANIA), the above referenced BIGAPE (Galoot), and ATECROW, count as evolutionary-related material.
I liked GAPYEAR (Hiatus between high school and college). I kinda wish I had taken one myself, when I was a youth, but I don't think it was so much a thing way back when the earth was still warm. :)
I'm a big fan of The Three Musketeers. I just finished reading Le Vicomte de Bragelonne - all 2400 pages. ATHOS is pretty suave, but I think Porthos is my favorite.
"Self-important minor official" TINGOD is also nice.
17A: "M*A*S*H" transport, informally (COPTER) - shouldn't the answer have been Chopper?
31A: Hoppy brew (ALE) - shouldn't the answer have been IPA?
33A. Vest openings (ARMHOLES) - what about neck and trunk holes (so to speak)?
Additionally, the grid seemed strewn with unpleasant remains and fossils like CNN, APPT, OME, TAUR, BCC, NCAA, WMD, NMI (?!?), SYL, and ONA.