If I kill someone, and five lowbies are standing around, I will only get 1 out of the best 6 items, if they all choose wisely. That is the best case scenario given sensible lowbies, and I wouldn't like it much. I'd rather they get the chance to full-loot but grab a pile of junk instead of the good stuff.

Also, it would stink that I can't even grab the one good item I want before more enemies arrive on the scene.

And how do you factor in butcher, or ritual of abominations, where the loot all gets put on the ground. Do you make picking stuff off the ground lag people? If not, orcs, rangers, ragers, liches, necros all gain advantage. If so, what about people are trying to retrieve a disarmed weapon? They'd be lagged a round before they could wield the weapon they'd just picked up.