The startup-scene dev message board Hacker News has an "Ask HN" section, and I used it to ask what developers want from a desktop in 2017. https://news.ycombinator.com/item?id=12703836 Here's a summary of what they said:
* Make upgrades painless.
This is often presented as "make it LTS or rolling", but in digging further, it's almost always "I don't want to have to devote a day of downtime to upgrading twice a year".
* Other improvements to updates (not necessarily upgrades): make them happen in the background, and provide a way to roll back if something isn't good. Also this for user tweaks rather than just updates.
* Give the ability to have package X move at a pace I choose. Separate dev stack from base OS.
* Hardware compatibility just works. (Wifi, sound, HDMI, graphics, suspend, etc.)
* Mixed DPI multi-monitor support.
* Look nice, better fonts, general usability, etc.
* Cross-distro packaging
* Containerized GUI apps