Well, I have a way of seeing the problem as just a temporary one, since I like to make extensive use of pilaging, which gives the railroad and rodoviary system a great problem when the time comes to a counter-attack. And, if anybody tried it, gives a great blow to the AI priorities and tactics.
If the RR could be "airlift" equivalent, then the problem does not change, if it is "instant troop reorganization". When it gets latter in the game, I think it is reasonable that we can get "instant" movement, specially if you think that that unit is not a troop, legion, batallion or something, but a representation of forces that moved during that time of the year; each battle could be just a representation of many battles that culminated with a determined outcome.
But that's just me.