If you take the time to read through that (very partial) list of cruft and footguns in X11 it probably makes it a little easier to understand why a clean-slate approach was able to attract momentum and why many hands-on involved developers were relatively tired of X11. Critics would of course respond that backwards compatibility is worth the effort and rewrites are often the wrong call, etc. It's the Python 2/3 debate and many others.
An X12 was briefly considered by the community before adopting Wayland: https://www.x.org/wiki/Development/X12/
If you take the time to read through that (very partial) list of cruft and footguns in X11 it probably makes it a little easier to understand why a clean-slate approach was able to attract momentum and why many hands-on involved developers were relatively tired of X11. Critics would of course respond that backwards compatibility is worth the effort and rewrites are often the wrong call, etc. It's the Python 2/3 debate and many others.