Actually, if you did downgrade, no one could ever tell that you were at one point on Lollipop, so I don't see how that would cause warranty issues unless you totally bricked the phone while trying to downgrade (which is a possibility).
Can this be warranty claimed for a replacement device? Since i was forced to upgrade, despite the fact I opted out a month ago, today i found my phone to be asking again. Except this time it was a now or later button, latter would only chose a time. This is the worst feature reduction upgrade i have seen yet.
Ironically the "congratulations successful upgrade" notification will not go away. Tapping it to look at the message just brings up a white page with a spinning wheel. Putting your head to the phone to talk works till you take it away and the screen never comes on. On that note new calls the screen does not come on with out pushing the lock button. Those are bugs, that I have seen in an hour. Don't get me started on the terrible interface.
I can't speak to the aesthetics only the issues. Do you still have extended warranty? If so, you can get a replacement. If not, I'm not sure what Verizon might do other than offer you early edge, if that.