It depends on whether their reasons for "absolutely having to have X11" hinge on actual compatibility with e.g. old binaries or wanting full remoting without streaming pixels.
This project would satisfy people who really actually want Wayland, but were upset by transitional pains or interactions they had around it and want to stick with X11 just-cause while getting some similar benefits. This arguably does describe some people but not sure it's a whole lot in the long run.
But who knows, maybe this could also make an easier to maintain XWayland some day, or a nice basis for implementing more esoteric X11 bits down the road vs. the older Xorg codebase.
This project would satisfy people who really actually want Wayland, but were upset by transitional pains or interactions they had around it and want to stick with X11 just-cause while getting some similar benefits. This arguably does describe some people but not sure it's a whole lot in the long run.
But who knows, maybe this could also make an easier to maintain XWayland some day, or a nice basis for implementing more esoteric X11 bits down the road vs. the older Xorg codebase.