This season's ender was about what I expected, the running continuity hasn't ever been a strong point for South Park, as they've always been a snacky issue/gag of the week show. They started to dabble in it in season 18 and it kinda was working, where there was just a thread of minor continuity. "PC Principal Final Justice" was just kind of a weak episode overall, it felt rushed, but not in the good way South Park rushes to make a funny episode. It feels rushed to tie up all the loose ends and get something coherent out of the season finale, which leaves the episode feeling kinda thrown together in a bad way and tossed out. Really they had a great chance to put together an episode that basically said; "want us to tie up all the loose ends for the season? Well fuck you! We're gonna do something really stupid and funny instead!" Which would have been amazing, instead they tried and failed to wrap up a season's worth of continuity in a funny interesting way.
Really for season 20, I hope they go back to their roots more, go to the snacky gag of the week style, and knock it out of the park. Seasons 16 and 17 felt like the pinnacle of South Park and they will never out do "Butterballs", season 18 felt like it was on the start of the down hill swing, 19 feels like a train running away down hill. The entire season was partially poisoned by the running transphobic gags, using Caitlyn Jenner as the template for all of the worst transphobic stereotypes. Honestly I don't like Jenner, she's an awful example of a trans person, not Zoey Tur bad, but she certainly isn't doing the community any favors by trying to speak for us. Really in the past transphobic jokes in South Park have been pretty tame and quickly brushed off for funnier jokes as soon as they hit. This season exemplified how it was failing with Jenner, running bad jokes into the ground so hard that they swung back around to funny, then became unfunny again.
Honestly I hope season 20 is the final season of South Park, they've gone down to 10 episodes a season now and it's just feeling like Matt and Trey want to move on. I can't blame them either, season 20 is their last contracted season, it feels like a logical endpoint, if they do more they're gonna run the risk of becoming The Simpsons. Just circling the drain stubbornly on nostalgia value alone. South Park has been great, but these last two seasons have been kind of weak, Matt and Trey seem tired with the whole thing. So I'll stick to the opinion that maybe it's time to put this series to bed, or perhaps flip the status quo and do a time skip.