Land-based artillery (
howitzers, mortars) having the capability of indirect fire on the map would sure be nice, with the ability of mission builders to specify a target area for particular battery (
while risking the abuse of some very unrealistic applications of artillery by some mission builders! 
). Currently, ship guns fire at targets beyond visual range, or at least a very long way, but land-based guns won't fire at anything unless it's directly in front of them.