I'm not sure what it is you're actually selling. More documentation or practical examples would be great. I'm not willing to create an account / sign in to find out stuff like that.
Latex Workshop for vscode [1] is catching up fast. It doesn't have Mendeley api support yet, but if you use the desktop client for syncing, it works perfectly and is under very active development.
As a university project, I did something very similar, only using a malicious app. The app would monitor the device state, and record gyro data as soon as the screen was on, but the device was locked. We didn't have the time to properly implement a decent classifier, but the data collection was surprisingly effective.
1. HEADLINE: A way to have different scaling for external monitors hooked up to my HiDPI laptop.
Currently I need can only set a single scaling factor, so I need to ajust my laptop screen resolution to match scaling of the external monitor. If that's not possible, a way to automatically set resolution and scale for both screens once you hook one up would already save me a lot of manual switching and restarting lightDM!
2. HEADLINE: "Native" multitouch gestures like 3-finger swipe to change workspace.
There are some programs that can do this already like xSwipe and Fusuma, but I expect this integrated with a nice and easy menu.
3. HEADLINE: Better battery management.
Battery performance under Ubuntu is often much worse in Ubuntu than Windows. TLP helps, but it's not enough.