People are allergic to any "fork action" of bitcoin. That is why XT failed so miserably, I am not sure if that proposed BIP of yours is not conservative enough for bitcoin purists.
Also I doubt that any changes that will push bitcoin into even more anonymous and private state will ever happen, it will be quite opposite route imo.
That is not the only reason that XT failed so badly. Their were some serious doubts about the intentions behind the fast push of XT. The main problem that was being tackled was good imo, but all the other stuff they tried to sneak in there should not have happened.