Android P impressions:
Wow, the "gestures" on P make no sense. It's too focused on app-switching. And while it's cool to slide the pill to the right to "alt-tab" between two apps, this was always available as a double-tap on the app-switcher button, which I think works faster. Alt-tab really didn't need to become a gesture.
Pulling up for the app drawer is terrible! It went from one swipe up to two swipe ups or a really awkward long-swipe up past half the screen. It's clunky and prone to going into the app-switcher window. To ensure you get it right, it requires stretching your thumb/hands further up with your swipe-up. Seriously, how did Google's designers think this was a good idea? It's terribly unintuitive.
This is the most half-baked and ill-thought of idea I've seen Google implement. It's not even a full fledge gesture system -- it's this mess of buttons and gestures. And as mentioned before, it doesn't even eliminate the lower bar to allow for more screen space. Google could have just updated the app switcher window from the old roller dex style to the new paginated one in P and been done. The gestures gain you virtually nothing, and breaks the app drawer. I went back to the buttons.
I'm still messing around with the rest of P, but is it me or did P get a ton uglier? The quick toggles are hideous and in general the notification pull-down UI is messy. Why is the upper bar black while the quick toggle space gray (in dark mode)? Why did they break the uniformity of the notification pull down + quick toggles in Android O? In fact, why do the Vibrate icon, Wifi icon, data icon, all drop into the quick toggles window? Why don't they stay in the notification bar (Edit: I know the answer to this now, it's for the notch!)? And why are the toggles now this blue theme? What is this, Honeycomb?
I also think they crowded the app drawer with those two large quick buttons that you can't customize. They just populate whatever they think you want to do. Uh, sorry Google AI, you're not that smart at predicting what I want to do. And now you've taken up two giant ugly buttons in my app drawer.
Is Google trying to make everything ugly?
Everything feels so half baked. Dark theme only darkens the quick toggles and the app drawer, but not the system UI, where everything is still white. If your theme is set to dark, notifications are white. Super inconsistent.
Honestly, Google is really going astray... I have no idea what they're doing.