All things SL is claimed to solve are solveable with unique
addresses too, as long as you've got enough of them. The rest is
just simple (perhaps tedious) work that every operations-aware
person I know of would prefer to madness.
All right, how do you make internal site communications completely
oblivious to a change in your externally-visible routing prefix?
(Not everyone accepts that this is something necessary to achieve,
but some insist that it is.)