Hey, guess what?
X is not network transparent.
No, really. I mean, it was, but it isn't anymore. Why? Because nowadays everybody uses SHM and DRI2, which don't work over the network.
So unless you're using Motif, then all X is doing is shipping bitmaps over the network, and doing it in an extremely chatty way that involves lots of round-trips from server to client for every single frame, injecting huge amounts of latency for no reason.
But chances are you don't really care about network transparency. Chances are you just think it's a synonym for remote display.
Guess what else?
Wayland supports remote display.
Here's one implementation, and here's another implementation written by somebody else.
Now, technically, those projects do not add remoting to Wayland, but instead add it to Weston, the reference compositor for Wayland. That's because the Wayland developers follow the Unix philosophy: do one thing really well. Wayland is not a kitchen sink like X is. It's part of a stack of interchangeable parts, and there's no reason remoting needs to be implemented directly in the display server.