No. A snippet of chat log posted by Darxus (link below) shows how current minimalist X Window Managers can be ported to become Wayland display servers without the bottom-up effort of having to handle input and other events from scratch.
Another common statement is that “compositing is bloat”, but this is just the sort of concept Wayland seeks to avoid. Wayland replaces the X server completely, making the path between applications and graphics buffers more efficient. Yes, a lot of things are done in GL land rather than 2D, but given the greater efficiency of Wayland overall I’d hardly consider it bloat.
Some work would be required still, but I hope to see some of my old favorites get ported.