Wadi and Gully

[leonard]

Being very late, and at this point inconsequential, I'll throw my bit in.

Having started with wadis in Afrika Korps and Desert Rats, I've always understood wadis as inverted hills.Thus they were treated that way. The new movement chart allows vehicles to move over the sides, but not much else changed.

Gullies I think more as natural AT ditches. That would take care of the technical invisibility beyond 1 hex. And with the new movement chart, vehicles can move into them.

Wadis/Gullies in Desert Rats / AK are at ground level ; there's nothing like being 20m lower. So, there was no LOS problem for being in a gully, at that time.
4th Ed rules made entry of a gully by a vehicle possible. However, the -20m location ruined the whole thing.
And you have to carefully read the 4th Ed Terrain charts notes to realize it.