This is a situation where appealing to the minority makes the most sense. The way I see it if you disarm someone then you shouldn't get to pick up that weapon straight out of the inventory. But if you kill someone you should be able to pick up their weapon right away. It is loads more convenient, and seeing how the weapon is going to be right next to them 9/10 times what's the difference? Better to make the rare situation where you would lose a weapon easier as it in no way hurts the game.
The other topic that has cropped up here (animations for looting), is a situation where appealing to the majority makes more sense. Only a few people want some kind of animation for looting bodies. And even less of those people would care enough to complain or not buy a game based on it.