For practical purposes, the problem with Wayland from the WM-dev's PoV is that you're either implementing a huge project or you're depending on wlroots, and wlroots still isn't where it would need to be for implementing a simple window manager to be as easy as it was with X11.

From the Wayland devs' PoV, mainstreaming Wayland successfully shifted responsibility for doing most of the heavy lifting in the graphics layer from the neglected X-Windows project to the well-established KDE and GNOME. The state of wlroots and the ecosystem of personal WM projects is unavoidable collateral damage.

For an individual developer, perhaps the thing to do is take a page out of bbLean's [1] bag of tricks and implement your WM on top of one of the big two desktop environments.

https://bb4win.sourceforge.net/bblean/