Funny, I used the Nokia N9 back in the days and the UI of (what was called Meego back the IIRC) was head and shoulders above everyone else. I believe the they were the first to have general gesture navigation so your comment about reinventing the UI is somewhat off the mark. Android implemented things after them, it's sort of like the argument that unix terminals should adopted ctrl-C for copy because it's the "standard".
I actually bought a Sony Xperia 10 and sail fish because I wanted the UI back so bad, but unfortunately I have some apps which didn't seem to work with android emulation (mainly banking...)
I am not saying the gestures in Android and iOS (app switching, etc) are actually the value add, but in fact things like toggles for options, or a "=" where the options are available to turn on/off. Sailfish forces gestures for things inside an application as well.
No doubt Meego innovated on ideas, but just because they came up with something doesn't make it "good" and just because Apple/Google copied it doesn't prove the validity of the idea.
To that point I would prefer we used more screen real estate (Android, iOS, whatever) and REDUCED the usage of gestures, it would end up being faster. It sometimes takes me multiple attempts to swipe from the bottom on a Android/iOS to get it to do something because I have a screen protector and/or case and the way I'm interacting the with the device is different than the developers who might have worked with a "nude" device.
The screen protector/case issue made UI navigation even worse on Sailfish devices because you had to use this gesture inside a program, not just to switch between applications.
Ubuntu Touch also has a swipe, but from the side where a screen protector is slightly less likely to affect it's ability to register the gesture.
Tbh N9 is still way ahead than today's Android experience imo.
It's also more consistent gestures experience than sailfish. Here you know the gestures are basically for "window/app management". Everything else - they look like regular Android apps.
I actually bought a Sony Xperia 10 and sail fish because I wanted the UI back so bad, but unfortunately I have some apps which didn't seem to work with android emulation (mainly banking...)