Wayland is flawless for what it claims to do. The issue is you can't replace X Org with Wayland, you can only use Wayland combined with other software to replace X Org. This is the biggest issue with Wayland: "Wayland is a replacement for the X11 window system protocol,"[0] but you can't actually replace x11 with it. What they should have done is make sure all the features that x11 had were supported by Wayland. By this I mean user facing features like copy-paste and color management. (And if someone thinks copy paste is not secure or whatever, let there be a flag to disable it or something). But instead they wrote a specification that when implemented replaces 90% (lets say) of X11. And since there are multiple implementations of the Wayland server you cannot rely on the other 10% to be present on any given server. If they had not written a specification and just released x12, or if they sanctioned only one specification, or if they had added more features to the specification then the there would be no problem. They still have room to add more features to the specification which I hope they do.
[0] https://wayland.freedesktop.org/