The fog of war had been talked about before, but what kind of FoW do you want? Realistic, where units have a forward cone of view so there back is exposed and you cant see past obstacles? Would the mini-map still be revealed enough to see the layout?
Either way that this is done could have impacts on certain aspects of balance. See i thought about how it would affect dwarves, since they are of the lowest speed i am thankful that the map is revealed, i can see what is coming and maneuver, but with Fog of War the disadvantage of speed gets just a little bit more severe. It would be very exciting non-the-less.
It would also add a whole new attribute to units in terms of balance, Vision. Would everyone have the same vision? Or would Elves with their stupid eyes have the best vision range? (only when their stupid long girly hair isnt wavering in their stupid faces)
But then some units might have WIDER cones of vision, or see in a safer radius, like a Beholder would see all around him. Then day/night cycles could further influence vision, team Evil would probably see a little better at night (and dwarves, dwarves totally see in the dark, SUCK IT ELVES)
Now, would ranged units have more range than vision? Or would a 60 range elf need a spotter ? I imagine 90-110 range Siege weapons would need a spotter.