No.
Xorg doesn’t support any of that. Multimonitor is nonexistent if you want to use it on a desktop, Xwayland still suffers from the lack of multimonitor (fractional+integer) scaling, and it tears horribly if you don’t want to use inefficient and annoying vsync (Wayland’s is fine).
Xorg is feature complete for its time; not for this time. The opposite goes for Wayland. Technically it’s a “feature” that any application can keylog on Xorg, that doesn’t mean that they should be free to do so without limit on Wayland too. If that means Wayland isn’t feature complete and Xorg is, then so be it.
One monitor, one framebuffer, an old use case that for some doesn’t even exist now, inefficient and slow tearing prevention, laggy vsync.
That wasn’t a multi-monitor desktop setup. That was a hacked together multi-display, single-screen setup.
Also why would you link an LD_PRELOAD attack? That’s not Wayland-specific in any way. Any other protocol and library is vulnerable to that too. But let’s point out one major issue with that: the LD_PRELOAD needs to be loaded in before the compositor in order to be relevant. With X, you can do that at runtime. Let’s also read the README from the repository:
Wayland isn’t the only software we need for a secure desktop; it just handles making the display secure. For libraries and application sandboxing, you want Flatpak, and we’re making progress on dynamic permissions there.
So? What’s your point? Nothing here is a Wayland-specific argument. Your setup wasn’t functional, it was fundamentally a hack, and one that not-NVIDIA/Intel/AMD hardware doesn’t support. Your argument is falling flat on its face.