I don't think there are many applications that refuse to work if the MIT-SHM, SMT, or DRI extensions are not present. They've never been guarantees, after all. The apps will just run slower, but still work over the net. Apart from that, client-side text through Xft/XRENDER, or videos using XV or GLX are unaffected and in my experience work very well over a 100 MBit/s LAN, in this case RDP and VNC don't really work better.

That's true, there is even an example that moves windows between displays in the gtk-demo program that comes with GTK. GNU Emacs supports it as well I think.

That's what made me switch as well two years ago, an NNTP server, static IPv4, and a native IPv6 /48 block :-) Costs 50% more than the previous ISP but I don't regret it.

That's exactly what I thought. At my university we were equipped with a bunch of Ultra60s that were upgraded from Solaris 7 to 8, from 8 to 9, and finally from 9 to 10. None of these upgrades slowed them down in any way, at least not that I noticed (they did get memory upgrades however). Now I could understand if Oracle dropped support for the Ultra60 with Solaris 11, but for a Blade2000 or Ultra45, which may be just a couple of years old? That's a surprise. I have an Ultra45 myself and I'm not at all happy with this, especially since Solaris 11 Express looked quite promising on the machine.