The game has changed since the quick proning appears. It was a lifesaver when someone hits your back. I think people don't like prone because of the hit boxes. And it is true. When someone prone it's sometimes impossible to hit the player.
If hit boxes had been proper, players wouldn't have prone so often.
For me the best situation is to work on the hit boxes and remove that annoying prone delay. Everyone can prone, so I don't see any reason for this delay