Cox has done a good job curating the playlist, using a similar "burn and turn" methodology that they used to use with B98.5 when B played a lot more 80s and 90s hits. That is, they would test a bunch of songs, play the hell out of them, test them again, remove the burnouts and add some new stuff that tested well, rinse and repeat.
The general trends I have seen over the years with them:
1) When they first started in 2006(?), they played a bunch of pop in addition to classic AOR. That has gone by the wayside except for the aforementioned Billy Joel.
2) Their core was originally 60s-80s classic rock, with emphasis on classic artists, and not so much 1980s MTV/hair bands. The 60s stuff was the usual--Beatles, Stones, Doors, Who, and the like.
3) Over time, they have almost completely removed the 60s. The notable exception is Hendrix, with some Stones.
4) Over time, they have been playing more 1980s MTV (A Flock of Seagulls, etc.) and hair bands--especially "oh-wow" stuff like Twisted Sister and Quiet Riot. But always stuff that might have been heard on an AOR station back in the day. Sometimes they push the limit on the soft end like with Toto and Men At Work.
5) They seem to be de-emphasizing the 1970s. Not removing it entirely, but easing up on the 1970s deeper cuts.
6) They keep trying to play more 1990s, and they seem to keep hitting the wall on them. They've never played grunge, but they seem to have difficulty with even more mainstream stuff like Hootie.
I just checked what they've been playing since 4-5 AM today and here's what I see that seems to be outside the 1970s-1980s AOR core (or otherwise of note):
1) "Magic Carpet Ride" by Steppenwolf (1968) - not what I would expect.
2) "Civil War" by Guns N Roses (1991) - really an 80s leftover by an 80s band
3) "Da Ya Think I'm Sexy" by Rod Stewart (1978) - probably an "oh wow" cut, since Rod Stewart is in their AOR wheelhouse but not this disco hit.
4) "Signs" by Tesla (1990). It's interesting that they played the remake instead of the Five Man Electrical Band version from 1971. 1990 seems to be closer to their core window than 1971.
5) There were a few artists that push the softer/poppier limit of AOR (Joan Jett, John Mellencamp, Fleetwood Mac) but still got played on AOR back in the day.