Meh. They never bothered to remove the signs in the first place which is the most obvious necessary change. Why the hell would the Germans have left signs signalling mines to the Russians?
None of the other sides signal the mines they lay. It's pretty ridiculous.
Because none of the other mines are basically guaranteed a squad wipe when infantry runs into them (aside from when the squads bunch up, which is roughly 90% of the time ) and the others cover a lot less area.
The SU Defensive Tactics PMD-6 Mine can have it beat maybe, but it's doctrinal and on Defensive Tactics so I don't really see a problem with it.