> If applications handle their own decoration and Wayland does its own window management, how do we get the variety of window management systems we have now (tiling vs. "standard", virtual desktops, etc.)
> The Wayland architecture integrates the display server, window manager and compositor into one process. You can think of Wayland as a toolkit for creating clients and compositors. It is not a specific single compositor or window manager. If you want a different window manager, you can write a new one.
That way people can just build and modify existing behavior rather then having to write a entire new window management system from scratch. That way they can concentrate on the functionality they desire rather then get caught up in replicating basic/common functionality correctly. Which seems a much faster way to get a large amount of customization possible.