I'm all for it stanislao! When you have a working mod I'll be one of the first to implement it on one of my maps. I'm thinking positive here so let us know when you get it figured out.
While I can understand why it can't be done it is a shame. Flying along in Lock On and seeing ground vehicles drive on realistic roadways, it certainly makes me wish we had that in IL2. With the efforts going into the new maps by so many, this limitation must be frustrating.
I'm not much into modding myself either, but isn't it possible to perhaps just change a simple texture (CurveRoadTexture or something like that), if it does exist, of course...
It's one thing how IL2 engine maps the roads on 200m basis, but there must be some textures avaible to represent that?
Or is there only one "straight" road texture applied as need, causing these sharp edges?
Otherwise, one could simply redo the curve-texture and see that applied in game? Okay, this would cause some "snakelike" diagonal roads, but far better than those sharp zig-zag-roads....
As for waypoints, if really necessary, people would be able to make their own curve waypoints for their columns, as most maps/missions don't offer hundreds of columns all over the map, but less than 10 in a rather concentrated area.