a. Completely automated update option, requiring no password prompting or manual updating.
b. Policykit or some such thing with a time-out to avoid having to enter password multiple times in rapid succession. (For example, you open Software Manager, then try to perform updates, having to enter your password twice. With a Policykit time-out like Ubuntu has, you'd only have to enter it once.)
c. Make Software Manager only ask for a password when you attempt to install or remove a package. I know it's a program that launches with root privs right now, but if integrated with Policykit like Ubuntu's Software Center you could browse apps without having to put in your password first.
d. Is there a secure way to get rid of password prompts altogether and instead have the "allow" prompt similar to Windows? If the system for it could be made secure, the only insecurity I see would be the threat of someone using your computer while you're away, but you should be locking the screen in that case. Perhaps this decision was intentional, but I can't help but feel it was overly anal as, again, users should really lock their screens when around someone they don't trust, and if an untrusted party has access to their computer they could do something else malicious.
2. Automatically pull from closest software sources in parallel. While the prompt for local sources and ping thing is all awesome, it could all be automated by default so users don't have to worry about it, and it could pull from multiple sources so that updates are downloaded much more quickly. There could be an "automatic" option somewhere in the sources config for this.
3. High DPI improvement: In Ubuntu 16.04 they have a slider for scaling the entire desktop, just in case you want more desktop real estate and want windows to be smaller on your big 4K monitor than "double". They also have it in the "display" section instead of "general" which seems more appropriate.
4. Indexing of your files. I'm not sure why I find updatedb.mlocate running every now and then indexing stuff when the Linux Mint panel doesn't allow searching through any local files besides the 20 or so most recent files opened. This is a feature I loved about Unity's "lens", being able to pull up any movie, song, document, etc from the menu. Ubuntu has an option to disable this indexing if someone doesn't want it.
5. Is Mint's SAMBA "secure" file sharing broken by default? I've always had to use the "Guest access" option because I could never get sharing working without it. It seems broken by default although I'm sure there is some way to get it working with some tweaks, but it should work out-of-the-box.
Just some ideas!

Thoughts?