If you want thin client like behavior, you should look at stuff like Waypipe or just outright using RDP directly, both of which are much better at the job of "display remote graphical application on my computer" than X11's client-server design ever managed to accomplish.

If anything, the variety of alternative solutions for that today -- everything from single-app to high-res full-desktop game streaming -- are much more robust and viable on modern networks than the X approach ever was, even if it was a neat-o "freebie" thing that fell out of its design. You get what you pay for, I guess.