Classic themeless grid layout, a triple-stack of long answers in each corner. I like how John pushed it, though. Very nice to get four additional long slots worked in — 16 long slots give you so much potential for a huge quantity of great entries.

The SE corner resonated with me, Jill and me an INTERRACIAL couple in a STARTER HOME. I asked Jim Horne the other day what he thought made for a great themeless, and his thoughtful reply was: needs a little something strong for everyone. I'm sure INTERRACIAL won't do much for other solvers, and it might even offend. Good thing there are other parts of the puzzle!
I liked that John worked in a good range of entries, from NAVEL GAZES for the introspective, to a TITLE FIGHT for boxing fans, from the OPEN BORDERS of much of the European Union to the ECOSYSTEMS a hiker might pass through as he/she ROUGHS IT.
That last answer brought a smile to my face, knowing that John and Mike Hawkins are hiking buddies. I feel privileged to have made contact with so many constructors, and seeing little flashes of their personality in a puzzle makes me appreciate it that much more.
So many of John's long entries worked well, although I didn't care for LIEGEMAN or PIMIENTO. (Mostly because PIMIENTOs are disgusting.) Not surprising to see that these particular long slots were the ones to sing the least for me, given that they 1.) run through a triple-stack each, and 2.) intersect each other. The more constraints, the harder to make your long entries sing.
A pretty clean grid, with one notable exception: DOGY. This is personal preference of course, but any time the dread "variant" tag is required = no bueno. I tend to gloss over a handful of minor RES, MOC, ETH, ELL crossword glue. Hard for me not to dwell on a DOGY; nice to see John equally thumbs-down now that he knows it is a variant.
Loved the clue for Mary SHELLEY, who wrote "Frankenstein." Created a monster, indeed!
Some strong entries, and mostly minor glue to hold everything all together.