Yeah, quite. And the XRender case is crucial for getting scrolling of large text windows to work efficiently over the network (since you don't have to retransmit a giant buffer every time, just a bunch of glyph positions).
Apparently the only way this will work in Wayland is for every single toolkit to implement its own remoting protocol, probably all with regular compatibility breaks and all handling authentication differently and all with most of the same failures of the X protocol.
This is, apparently, progress. But we can remote the GIMP and stuff that mostly does graphical output of non-glyphs or never wants to scroll them really fast now!