I don't this is really necessary, and expect the additional complication will far outweigh the benifit.
Real world, when you set up in OW,
- You have prepared a killing zone and are ready to blast the bunch that step into the trap . . .
- OR, you are a lightly armed scout troop that intend to bug out at the first opportunity. . .
- Rarely, you are a lightly armed troop that has blundered into something a lot bigger than you, so blast them before they get you . . .
What I think you are aluding to is actually giving people the chance to evade something nasty coming their way, which would remove clipping to a large extent by giving the target the opportunity to regroup to face the threat. In practice clipping represents the element of surprise, where an over-extended formation is caught out and the attempt to re-group causes the entire formation to run away.
However, in the spirit of discussing/spit-balling the topic, two thoughts for house-rule modifications:-
- Scouts on OW might be given the chance to react differently to a threat, perhaps by taking an activation test to perform a single withdrawal move rather than fire?
- Others on OW might be given the chance to keep on firing until over-run - so treat their shooting as a Sustain, but remove their FF capability. This option is not available to formations other than the target.