I hear you about the problems with it and mainly agree. I think it is only going to help in situations where things are only going to go one way and there is no real commanders’ choice involved. I think this is why I noticed it in this game, because as you say, the British commander was forced to decide whether to extend command effort to dismount his carriers or engage the Germans with his tanks. This looks like a false choice to me, because it implies that the Carrier platoon would give him that choice.
So I think an automatic dismount would work when:
1 – Troops in soft skin vehicles get “suppressed” (i.e. no move) results from any type of fire and there is a survival benefit to doing so. If the troops can still move then the effect doesn’t kick in.
2 – Troops in AFVs get “suppressed” (i.e. no move) results from air attack.
Lots of things like this are in niche but important situations. So normally rules have decent approaches to suppression, but to my mind troops with a covered retreat should always be able to do – you can’t meaningfully ‘pin’ an enemy who can withdraw down a trench / sewer / beyond a ridgeline.
I am not too worried about IA drill on being ambushed because I don’t think one side should be able to invoke a rule to invalidate the results of the other sides actions, they need to play the game/fight the battle. So in that instance, if the troops’ initiating the contact suppress the targets, then the targets need to rally or whatever to charge the initiating troops.