This is prob more of a mod, but...
I think everyone and his mother uses new terrains these days... and really, why shouldn't you? They're great, go get them. NOW!
Anyway, what I mean is: The map simply isn't sophisticated enough to convey the needed info, especially in places that may be plain ground or forest either way. With the new terrains, terrain knowledge before deployment is necessary and useful.
I'm sure no military force worldwide deploys anywhere without knowing where they are fighting first. So what I was thinking is somesort of pre-mission interface symbol or such showing the terrain of the mission. Say, even something as simple as "Forest", "Plain", "Desert", "Warehouse", etc would be great.