Realism wise the whole thing is wonky. I could see it actually taking less time to "get all" than to rummage through someone's corpse looking for a single item.

Assigning lag to the sacrifice of limited items isn't a bad idea, but it won't fully solve the problem.

Another possible idea: when doing a "get all" sort the items in order of least to most limited, then secondarily by most to least weight. Given weight and inventory restrictions this would render "get all" as non-beneficial as possible for the getter.

One issue with the above is that sometimes "get all" is completely legitimate. For instance, you attack a group of two and kill one guy but have to evacuate before killing his friend. Maybe you drop a "get all" on the first guy's corpse before running away, fully planning to sort through it later and return what you don't want.

Possible fix to the above: only invoke the "sorting" behavior when the getter is not currently in melee. This makes no sense from the perspective of realism, but that's true of a lot of things.