I have no love lost for Wayland, but this:

> Make easy things easy. Make hard things doable.

is generally unachievable. Instead, pick one:

- easy things easy, hard things impossible

- easy things tedious, hard things possible

(Unless you want to maintain two sets of interfaces in parallel.)

This is quite easy and very widespread to accomplish by having helper functions for common operations.

Yeah, obviously you have multiple levels of public interfaces, like how CreateWindow calls CreateWindowEx under the hood.

Do people recommend the API surface should be totally flat and the same for all developers?

Wayland makes it unnecessarily difficult to make simple clients. Gnome still doesn't support server-side window decoration and libdecor is an absolute nightmare and wayland-cursor doesn't even detect the system theme properly.