The NRL is actually trialling reducing this with the senior safeplay code. My competition the Proten Cup in old Group 17 land used it this year and it included only 2 allowed in the tackle (apart from within the 10 of the tryline) and 1 marker. Brought little blokes back into the game especially around the ruck and players had to actually know how to tackle with the right technique instead of just ganging up. Quicker play-the-balls too as in gang tackles you can have 4 players peeling off one-by-one to give the illusion that you're trying to get off.
Not the solution for all rugby league but was very enjoyable and a lot faster than the footy I'm used to. We are hoping to bring about more smaller competitions like this to increase playing numbers and get more people playing the game with less fear of injury.
That's what we want mate, more of the smaller nippier guys playing the game ,just like we had with the Tooveys, Sterlings,Langers,etc.
The biggest problem with 3 or 4 in on a tackle, yes it's
effective in stopping the attacker's forward motion and his offload, and repeating what you stated the adverse effect is more chance of injury to players both in the attack and the defence with head collisions,and the eternal amount of time it takes for defenders to peel off and the ball to be played.Giving a tired defence more time to gather their breath.