Not really. Systemd had the complete opposite problem, it did far more than the previous hackery of shell scripts. The complaints were that it was too big, had too many features, violated Unix philosophy and was less deterministic. Systemd had no problem fully replacing init, cron, DNS and Co. Wayland simply can’t replace X11 in it’s current state, it just can’t do a lot of basic things.

such as no massive gaping security issues.

That’s an utter strawman that doesn’t get any more true by repeating it. Nobody cares about display manager security at this point, since every app you run already has full system access anyway. Wayland security is like making sure the door is locked after the thief is already in the house. It might become relevant in a future when every app you run is in a Flatpak sandbox, but we are a very long way away from that. Even apps that use Flatpak are rarely sandboxed to the point that it would improve security. And on top of that, the sandboxing model Flatpak uses fundamentally doesn’t really work with a lot of Unix tools, e.g. how would you Flatpak something like make?