Yesterday was definitely the best "overall conditions" day we've had since the parks re-opened (not necessarily the "most magical day," but the best combo of park conditions for sure). I was there from rope drop at DL to the "park closing" announcement at DCA (left DL at 6, dropped the kiddo and my MIL off at home, and came back with my husband to DCA at 7).
I have rarely witnessed such low crowds. The crowd level we experienced absolutely rivaled the grand re-opening day (April 30) crowd situation, but with more open and longer hours. In fact, we waited longer for Indiana Jones on April 30 (35 minutes) than we did for anything yesterday. We walked by Pirates four times, from 9am to 5pm, and we NEVER saw a line outside the building. That is just... unheard of!
The temperature was also better than opening day (it was 92 then and about 84 yesterday). The food situation was great - no wait for morning Starbucks (!), mobile orders were immediate all day, we were able to walk into the Lamplight Lounge bar at 8:15pm - everything was just humming along! I'm also happy about the "masks required indoors but not outdoors" situation, which added to the perfect conditions as far as I'm concerned.
Honestly, I was kind of bummed that we'd bought the CA resident tickets when they announced the Magic Keys, but getting to experience a park day like yesterday made those tickets worth it.