The big problem with Wayland I see is that every small app needs to do everything (fonts, ...) which can be a lot of startup overhead...
(I'm 100% not a fan of using a single process for all terminals).
tbf in reality nobody uses X11 corefonts anymore. Even on X11 all typical toolkits like GTK or Qt have been doing their own client side font rendering for years.
(but X11 still supports server side fonts if you want to make trivial clients)
I don't miss the font mismatch, partial Unicode, and the wrong mapping of ÅÄÖåäö of X11 servers...
There's so many irritations with using Wayland that I continue to strip it out of installs. Not being able to correctly use push-to-talk in voice chat apps because of window security is infuriating, and one app crashing still takes down the entire desktop.