I apologize for not being clear; I was referring primarily to 4.4 "KitKat". Still have a tablet that I run with that on it (offline) to read ebooks. Quite nice. You are correct though - pre-4.0 was pretty rough.
Yeah agreed. I am torn presently between the feature creep and the fact that new phones are so physically faster computationally that Android can finally scroll smoothly.
Even my 2017 KeyOne with 2GB RAM and a slower class SoC runs fine; the only caveat is I've disabled GApps. I realize this is a large ask for some, but I think it's important to point out that Android itself isn't terribly heavy, Google's tracking is.
I'm quite partial to 4.2.2 Jelly Bean, the last release with the "Phablet" UI layouts meant for the Nexus 7. I had a Galaxy Note Ⅱ at the time, and it was easy to get that UI by changing the screen DPI setting or using a custom build like Paranoid Android: https://i.imgur.com/O8lSsXn.png