What are the not-a-bugs? Things like covering up a Wayland window will block it’s rendering thread indefinitely with no way to detect it happens to handle it. This can lock up some games, or cause you to time out in a networked application. Some Wayland core folks don’t want applications to know if their window is visible or not because it’s mild information about a user’s attention that should be private. Every game dev on the other hand is asking “WTF!?” as it causes their games to break randomly
Please don’t make up what “Wayland core folks” think. You don’t know it, and your claims are waay off.
It’s not about security. It was intended to allow the compositor to throttle apps to improve efficiency… Which of course in practice doesn’t work like this at all, because OpenGL swap buffers and Vulkan FIFO presentation modes were never intended to be used this way.
As for why that hasn’t been fixed yet, it’s not as big of a problem anymore:
Mesa (at least for Vulkan) and Xwayland gurantee one frame per second as a minimum refresh rate
toolkits and libraries use mailbox presentation internally and check frame callbacks themselves for when to render
xdg shell now contains a flag for apps to know to inhibit rendering because they’re hidden. That doesn’t guarantee that presentation won’t otherwise block though
a (set of) protocol(s) is being worked on to replace frame callbacks with a mechanism actually suited for OpenGL and Vulkan
Another mild example is that windows cannot be raised except by the user or by launching them. This is supposed to be a mild security precaution so a program can’t pop up a legitimate looking dialog over another application and trick the user. Realistically it means that applications can’t open and focus URL in your web or file browser. Instead they have to give you a notification telling you “Firefox is Ready” and make you do it manually.
That’s not even close to how activation works on Wayland, and no, it’s not just a security thing, it’s a usability thing. Apps can only raise themselves if the currently focused app gives them focus, so that random apps can’t cover up what you’re working on just cause they need to show you an ad or an “important” pop up question or whatever. If it doesn’t work for a specific app, make a bug report about it to the app.