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.
I mostly agree. I usually recommend Mint to new users, largely because their web site and defaults are very beginner-friendly. Mint is the modern version of what Ubuntu used to be 10-15 years ago. At this point I don't think Ubuntu has tangible advantages over Debian for new users.
I really like Slackware's site. It's not sexy, but it's functional, organized, and easy to navigate. The Zsh site is counterintuitive to me with that sidebar-that's-not-really-a-sidebar, and hyperlinks whose text requires the context of a header that is not aligned with them.
I just checked out Ubuntu's web site for comparison, and...uh...now I feel like I owe Debian's web site an apology. I guess the consumer desktop Ubuntu distro doesn't actually have its own web site anymore? I mean, you can get to it from there, but it's hidden under menus, and seems almost like an afterthought. Ubuntu's main web site is bizarre right now, with a prominent green "Download Now" button that does not lead the user anywhere close to downloading Ubuntu, but rather directs them to one of a rotating selection of signup forms to download various technical whitepapers like "A CTO’s guide to real-time Linux". That's a radically different target audience than the last time I went to their web site (and also a weird design anyway).
I guess this has to do with the fact that BDFL Mark Shuttleworth after putting so much money into Ubuntu finally wanted to see some profit (I think I read that Ubuntu was not profitable for a long time) and went in the same direction like RedHat Enterprise and Novell SUSE had been going. If you look at Canonical Juju https://en.wikipedia.org/wiki/Juju_(software) launched 12 years ago, and things like Landscape https://ubuntu.com/landscape which has been there perhaps more than 10 years as well, and now with Ubuntu Pro it seems clear to me that Ubuntu was not just meant to be a desktop Linux distribution. In fact, nowadays when I try to find an iso file for an Ubuntu installation I need to be careful not to end up at a download page for the Ubuntu server iso.
Anyway, maybe I should instead try out and be recommending Pop! OS to new Linux users soon. It seems very popular https://pop.system76.com/ ;-)