Colliding bodies could become very tedious. It may even prevent you from getting multiple kills with the saw, since you won't be able to run through people properly. I don't like the idea.
That alone is enough to end this argument, and that is still omitting the fact that corpses are rendered client-side to avoid the lag they cause. Allowing them to collide with people would cause them to have to be rendered by the server, causing the aforementioned lag.
Sorry, but I don't support this.