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.
The installer is the single one reason I can't switch to fedora. I have several drives in my machine and I like to separate them, but their installer scares the shit out of me. I can pull it off for sure, but I just don't want to take the risk