Debut — and another teenager! Great use of a revealer, interpreting MORNING PERSON as a person with the initials A and M. People initialisms are a well-worn theme type, so it's important to add an extra layer if you want to stand out. John does just that, as the MORNING -> AM - > "A. M. people" link is clever.
When you have four featured people, I personally like seeing representation in terms of male/female, ethnicity, and variety in their careers. I loved seeing AKIO MORITA, a giant in the business world, kick off the themers. Am I biased because I love being in Japan, where I blend in (until I open my mouth, that is)? Yup. I would have enjoyed seeing an African-American and a Latino perhaps, but what are you gonna do.
Without doing an exhaustive search, I can't say how easy it would be to incorporate another woman to balance things out. Sorry ALANIS MORISSETTE, your 16-letter name isn't favorable for crosswords. Chancellor of Germany ANGELA MERKEL? Twelve letters is an awkward length for a themer. AGNES MOOREHEAD, your 14 letters are also an awkward length.
Ah — ALICE MUNRO, sorry. Your literary power apparently was no match for ANDY MURRAY's serve. I still am a big fan.
With a theme based around names, I prefer seeing fewer names in the fill, as excessive proper nouns make me feel like I'm doing pub trivia instead of a crossword. I normally like ED HARRIS and Jackie ROBINSON, but perhaps with so much ELIZA, ROMERO, BRYN Mawr, AVON, FIRTH, DESADE, etc., maybe I would have preferred different long downs today.
The 10/10/13/10/10 letter themers makes for an audacious debut. I was especially impressed by John's upper left and lower right corners — big, open spaces, cleanly filled. Typically I don't mind a somewhat esoteric INO or CLU Gulager, but given how many proper names are already jam-packed in, I would have preferred different types of glue if possible — even a partial or abbr. to mix things up.
Similarly, ENZO Ferrari: I like your Z, but perhaps not today.
Nice revealer, requiring a little thought on a Monday. I like that.