For example, I'm using Debian, and I think we could learn a thing or two from Mint about how to make it "friendlier" for new users. I often see Mint recommended to new users, but rarely Debian, which has a goal to be "the universal operating system".
I also think we could learn website design from.. looks at notes ..everyone else.
Alpine & OpenBSD with CLI installers, minimalism, lack of bloat and strong KISS philosophies, they remind me of what Arch Linux used to be -- I don't want any crapware if possible (dbus, systemd, polkit, logind etc). Just nice and simple.
The only one I have installed is dbus, unless you want to manually patch it out it's pretty much everywhere (Gentoo is nice for this).