Here's the thing. It already exists; i'm using it on macOS. It's called Quartz.(which greatly inspired Wayland)
I'm just waiting for that brave soul to write an open source implementation for the BSDs.
To add; Wayland should've been API based, instead of protocol based. Canonical had the right idea with Mir (especially with native EGLStreams support), but they caved to Red Hat, zealots, and Co.
Hail IBM.
Mir is also GPL 3 which caused controversy compared to MIT, used by Xorg and Wayland.