> Yes, I know about x11vnc - and that's exactly my point.
What's the problem with x11vnc? You mentioned two use-cases: share desktop with someone else and connect from home to office. So x11vnc exactly solves first case and can be easily used in another one.
And no, having an unlocked screen is not a problem, since nobody can do anything there anyway because you'll see that (you can turn your monitor off if you're afraid of someone to see something). Even more, it's an advantage, since while talking to someone in your office you can say "Let me show you, come to my desktop... Look, I open this program, do this, click here and check this..."
> We have this nice super-duped-network-transparent GUI system which obviously should be good for remoting, but when it's faced with real-world task (the most popular real world task by far!) it FAILS.
It's not. This "nice super-duped-network-transparent GUI system" is what allows you to do that, and do it instantly, without any preparations, without patching X.Org or rebuilding weston from experimental git branch.
For me the most common case of remote desktop is: I'm home, I have not started VNC server since I did not planned to connect to office, but now I need it. So I SSH into my office machine, start x11vnc, do the job, lock screen and leave. Simple, no preparations, no firewall configurations, I don't even need admin rights to do that.