i was thinking about a mod, where land vision would be affected by the terrain.
for exemple, a land unit would not be able to see in the crater of badland/wonder. (depend of the high of the terrain...)
or a land unit won't be able to see what there is on the top of an hill. Exemple : your unit is on the low ground of badland, it won't be able to see what is on the high ground (hill)
could had more interest to stealth, even if T1 air scout are cheap, and would still be able to see everything.