Good S0ix support. At the moment, Linux mostly fails to sleep correctly on modern S0ix laptops, which happens to be most modern laptops.
This means the battery drains incredibly fast, and S0ix features aren’t being used, which is unfortunate as it has potential for quick wake, lid closed actions and limiting battery drain while asleep (since S0ix can eventually hibernate automatically from a sleep state)
Also the boot loader could be improved, systemd-boot needs to support secure boot natively so we can be rid of the slow, ancient and scary-looking GRUB.