> As far as I understand, window manager would work on top of Weston (with the exception of integrated beasts like KWin and Mutter which will replace Weston and talk directly to Wayland).
There is no window manager "on top of Weston", Weston is a compositor and thus it also decides where your windows go. Actually, the term window manager really only makes sense in an X world, where afaik every X client is allowed to move around every window as he pleases.
Also, Wayland is a protocol, not some kind of server, so saying that KWin and Mutter will "talk directly to Wayland" doesn't make sense. They'll speak to clients using the Wayland protocol and to the hardware using KMS/Mesa etc..