> It's not really a problem, because it only gives a hint where the enemy is without revealing the exact position.
Hmm, I don't know. This reminds me of the remote nade shelling that revealed enemy positions anywhere on the map, even if out of sight. I remember that you planned to limit the range where those explosions are visible for the player. Maybe you could add the same feature for opening doors? When you make opening doors visible only in a certain range of the player's units, enemy movement on the other edge of the map wouldn't be revealed.