As an admin
on a wiki affected in this way, I have to say that that feature
would not be useful. This is what the Transwiki: namespace is for. Import by
default to that namespace, and move to the new location; this leaves a
redirect behind, which is almost always a good thing, since links on other
projects will usually point to the Transwiki: page, and finding all links on
all projects is really not that much fun.
Why would links on other projects even exist, let alone point to the
Transwiki page?