I can say that I have yet to notice anything wrong with UConnect. The first cell call I made was loud, but I adjusted the phone volume down and subsequent calls are fine. I've never had a remote function fail, nor had a black screen or problem with the rear camera. I don't use the favorite artists or notifications, so I can't comment on those.
My other vehicle that has remote start and other functions via phone app won't start in my driveway. Never had that problem with the truck. I think it's related to poor coverage of the cellular provider that mfr. used for the system.
I don't use every feature so I cannot speak to all. I have never had a back up camera issue. Call volume was odd when I first bought truck but an update like 2 weeks later fixed it. Same thing with blank screen - even then I just turn hit power off and power on and it works. Only used Guardian for locks not RS but it worked everytime.
Name me one product that works 100%. Even Apple can't say that and they are clear leaders in regards to consumer software. Even my brand new iPhone XS does something funky every now and then.... but those are one off things that happen, I close an app, and it works fine again.
As far as immediate updates... what the hell world do you live in? Ever worked in anything remotely tech? Stuff like that goes through multiple layers of testing - goes back to fix bugs - testing - fix bugs - test - release.. etc. You can't just throw a patch out there.... that's how you end up breaking other things that are more important. Imagine they put in a patch to fix favorite artists and now the lane assist doesn't work. Coding isn't cut and dry, this stuff requires a lot of testing.