It's a good idea. At least, sooner or later, if HTC wants a more tactically balanced ground warfare they are going to have to consider the use of roads and their importance in the game.
A lot of things can be 'tweaked' for gameplay purposes. Instead of cutting down moving speeds to such drastic levels, you can always tweak it to something like "80% of the maximum speed for given vehicle" on off road terrains, and full speed achieved on roads.
For instance, if a GV spawns at a certain spot, and he has to go through a hill or a dense forest to get to the town, then finding the road that leads to the town and taking it would actually be faster than going straight towards the town. If the terrain between the spawn point and the town is a pretty much flat piece of land, then going straight for the town would be better.
This brings out a lot of new possibilities - road blocks(for blocking enemy supply convoy), road-ambushes, and a lot of battles revolving around roads and roadstuff(bridges, tunnels, etc etc..).
Ofcourse, this implies that a road system that makes sense should be implemented first. The only roads we have in AH terrains are between the truck depot and the town.
