Smoother window resizing
Currently windows are being resized in real-time, which can be heavy in several cases (especially those involving tiled windows), and is asynchronous by design (correct me if I am wrong) in the Wayland protocol.
This can be solved by having a clone ("thumbnail") of the window, either just stretched or blurred as well as in macOS, being shown whenever frames don't arrive on time.
A perhaps unneeded extension of this could be to limit the rate at which the resize command is sent to ~10 times per second in all cases, mixed with the mechanism above, in order to make resizing windows smoother on low-power machines and less CPU-intensive in general, at the expense of having a probably slightly weirder (see current maximize/normalize window process) visual transition between states.
Mobile devices and Windows/macOS tend to do this (plus the blurring) in some particular conditions, for example on tiled windows.
This is more of a proposal than of a bug or clear feature request, which started from some recent discussion in #gnome-design. Would solve #583 and similar issues.