Other argument is, that on some terrain, mines are optically nearly not visible. It would be hard to maneuver a tank around them, even if you know there is some, especially with the bad pathfinding of coh2.
Edit: And attacking mines with tanks: Bad idea, when enemy is waiting there for example with tank destroyers, and you have first to shoot mines infront of them with your tanks.
I think having the map knowledge of knowing few good mine spots is minor negative compared to the total effect of making mines more useful against super aggressive plays and blobbing. And these minespots would become common knowledge so that should balance that out soon.
Shooting mines with AFT instead of using sweepers or ID fire when you know enemy is waiting with AT sounds a lot like an L2P issue and not a balance one.
