Actually, it was not the roads and tracks that were attacked, but the trains, trucks and (of course) bridges. Tracks and roadways were quick (relatively speaking) to repair, but it took much longer and much more skilled workers to build trains, vehicles and bridges. The Germans became quite skilled at repairing damaged tracks and road sections.
Remember that in the MA, the effects of strategic targets is compressed in time. The time required in the MA to produce another train is only 5 minutes (the delay to spawn a train when it's destroyed); destroy an entire refinery and the most it's down for is two hours. Applying the same time compression to the act of repairing a section of damaged track or road, and it would be back up in the blink of an eye in the MA. Besides that, bomb craters only last for a few minutes anyways.
What I would rather see is for trains and convoys to affect not only rebuild times, but also limit supplies. Not limit aircraft, but just the availability of expendable supplies such as fuel, ordnance, and troops. I would also change the resupply effect of goons and M-3s such that it would take several to completely resupply a base that is short of supplies because its convoy got nuked.
I would even go so far as to suggest that a field stay down and short of supplies indefinitely in the absence of a successful resupply by goon/M-3/convoy/etc. I would also suggest that a successful resupply should not cause the instantaneous rebuild of all damaged facilities. Rather it should rebuild things after a certain amount of time, and in the order that they went down.
If we keep auto-rebuild such as we have now, then the effect on rebuilds from resupply should change. Right now, base objects will rebuild in a certain amount of time (15 minutes for hangers, 30 minutes for ack, etc) unless a convoy arrives or a supply drop is made. If a convoy or supplies make it to the base, everything comes up almost instantly and simultaineously. Instead, every convoy or supply drop that makes it should simply reduce the remaining rebuild time for each object, individually, by 50 percent. That way, there is always a small delay between supplies reaching the base and the objects returing to operation. Plus, objects should rebuild in the order they went down, just as they do now.
[ 10-16-2001: Message edited by: Rojo ]