I don't think it would be worth the effort. Making it would mean that the prone box would be kept smaller, though the box height is pretty good now in my opinion, and when ever someone uses the needle all the proned boxes of players would get adjusted to taller and returned smaller after the trace. I personally haven't seen too much cases when players hide behind players who wait for revives. They can't shoot through those player either, so it evens out a bit in that. Also, the standing player, if close enough, has advantage to move to a different angle faster to hit the target player.