Huzzah! That was pretty much my single biggest disappointment with Wayland. Although I like the visual consistency of server-side decorations, one of my favourite things about X11 is that when an app hangs or otherwise does something weird, the close button in the title-bar still gives me control over the app, I don't have to hope that it's still processing its event loop or bust out some arcane interface like Task Manager and guess what the application's executable is named.
Has anyone ever used those things for more than a single day? I honestly thought the current compositing window managers don't even support that novelty stuff anymore.
In the context that's not the point -- another plus for client-side decorations is that no synchronization is needed between the decorator and client for resizing.
Personally I think client-side decorations are far easier to implement reliably and would welcome them becoming default.
I use wobbling windows because it makes my interaction with the system seem more transparent. Rigid windows feel unnatural, but wobbly windows let me become absorbed by my task.