OwieB2003
Warlord
This is more of a general combat idea, but so much of it is terrain-based that it might as well be a terrain idea.. anyway: Have terrain give bonuses/maluses against specific attacks... e.g., archers and artillery attacking a flat terrain square from hills or mountains get a bonus to attack, unless the "flat terrain" is a forest or jungle. If an artillery unit attacks something in hilly/mountainous terrain, or in a fortress terrain enhancement, the chance of damaging that unit is VERY slim (caves and other natural terrain features that can shield against bombardment.. maybe a "protect against bombardment" unit order which would disable or severely hamper any bombardment attempt, but would make infantry attacks against the protected unit easier, being trapped and all.