I see one "problem"...

It breaks the background. Best example is the players jumping out of
a bad situation. Say they make a J2 (max for their ship) and their
destination is obvious. If the other side has a better J-drive, they
can be *waiting* for the PCs to exit jump.

That's a big change. Unless that was why you wanted to do it.

It makes it a lot harder to leaver your problems behind.

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com