Where hardware allows for it, it would be nice to have a system settings GUI way to configure vsync per application, so you can run games/software at full speed, and media players without tearing. (Yeah, Linux terminal FTW and all, but I use my PC for work most of the time and would like an easy way to configure this, I'm sure others would too)
I know X11 compositing is a nightmare, but tearing is something that I've only had an issue with in Linux, which is a problem for people who want to use Linux for media, but can't due to tearing issues, and when everything is sort of locked to 60FPS, but you still have tearing all over the place, it can get really frustrating.
I created a tutorial to fix this issue in Mint 18.3 Cinnamon on Radeon Xorg drivers https://community.linuxmint.com/tutorial/view/2388
I understand that different hardware configs will have it's own challenges, but having the option at least for the open source drivers on most Intel, AMD and Nvidia cards would make things look a lot more polished, even if it just starts with limited card support to begin with.
The open source driver actually work really well at this point, at least with my setup, so I'm able to play most titles in my steam library no problem, though having vsync always enabled prevents me from playing any fps games at all until I've changed a bunch of configs (which took a bunch of research on my end). It's not impossible, but it's one extra barrier for new people, and as Linux Mint stands now, there aren't a lot of barriers left :).