1. Wayland Fragmentation and Missing Features
Users criticize Wayland for compositor-specific protocols, lacking universal tools like X11's automation and remoting, calling it "security theater" and balkanized. "On Wayland, this isn't supported 'for my security' and my remaining options boil down to either using a tool that requires root... or a tool made exclusively for my DE" - mzajc. "Wayland is both bleeding-edge and obsolete simultaneously" - Qwertious.
2. Preference for X11's Universality and Simplicity
X11 praised for cross-DE compatibility, scripting (e.g., window titles), stability, and custom WMs without compositor complexity. "In X this is easy and the bash script will work with every DE. In Wayland you have to write a different solution for each compositor/DE" - mikkupikku. "X11 is backwards compatible, you do not have to 'keep up' with its changes" - badsectoracula.
3. Phoenix as Modern X11 Revival ("X12")
Enthusiasm for Phoenix's cleanup of X11 cruft, Vulkan/DRI focus, and Wayland-like isolation while retaining compatibility; seen as better than XLibre/Wayland. "Phoenix is a great idea. It's basically 'X12': removing the old cruft and making breaking changes" - kelnos. "A better plan than XLibre" - wmf. Skeptics note early incompleteness: "very few things work at the moment" - donio.