ORIGINAL: janh
The idea with the MP cost to the defender was along the same lines, i.e. binding the enemy like for example the role that the Armored Cavalry Regiments, scouts etc. had in the past, and possible even in present doctrine. Think of the 2nd ACR in Desert Storm. This effect is also absent with the present I-Go-U-Go system. Imagine that every deliberate attack, cost the defender the combat MPs (i.e. 2 or 3). You could half that penalty for hasty attacks, or double it or whatever in detail. To ensure the defending unit would still be able to disengage and move off a little within the 1-week time frame of the next turn, you could cap that "penalty" so that MPs for Inf are maximally reduced to say 10 and that of the rest to say 20. Then Soviet players would have some gain from attacking even if the losses were terrible, and the dynamics of 1941 might change dramatically. The disadvantage would be that the Axis would have to bite the same bullet later. But this "abstracted rule" would be plausibly based on the real world mechanisms.
I can't remember what it was called, but TOAW had a 'disengagement penalty' when moving the last unit in a hex that started adjacent to an enemy unit away and into friendly ZOCs. "Last unit in the hex" was the important part of the rule, as one could thus move in a high MP unit to evacuate the others first, and then pull out the high MP unit. I always liked this feature, as it gave a certain realism to withdrawing, and that disengaging from the enemy isn't always easy. It was based on various factors (IIRC moreso the difference between MP of the enemy unit(s) and your own. You could thus try to hold enemy units on the line by putting your high MP units adjacent to them. The reason being that for example, it's difficult for infantry to disengage from armour, but much easier for armour to disengage from infantry.), but sometimes the unit wouldn't disengage (or rather, lose so many MPs that it didn't have enough left to move away) and could suffer notable combat losses. In an extreme case, a weak unit could even shatter/evaporate trying to disengage. Usually, disengaging resulted in lost MPs and perhaps a small 'attrition' strength loss.
