It took me a while to catch on to the"pre" theme in today's puzzle, but once I did, I enjoyed it. In four rows, there were two Across answers that were related. The second answer in the row had a regular clue whereas the prior clue specified that it was "Pre-##-Across". I finally figured it out with 50A: "How emotionally developed people handle things" (MATURELY), which made the clue for 47A: "Pre-maturely" or EARLY. Pre-DICTION/AUGURY was a good pair. I also liked Pre-AMBLE/FORWARD.
There was some nice ambiguous cluing today as in "Thatcher's creation" (ROOF) - my first thought was Margaret Thatcher! - and "Pod creature" (ORCA).
I enjoyed the throw back at 39A: "'70s rock?" (PET). Remember those? They were pre-dated only slightly by the introduction of the Buick REGAL. Did anyone else notice a distinct ECHO in the puzzle with HAHA, GOGO, and OKOK?
I thought the pluralizing of BACHS was pushing it a little, but I did just read that Johann Sebastian Bach had 20 children, so maybe the plural was APTS after all. :)