Chipping around in the back half is an easy fix. All backwards kicks are play on and there is a shotclock forcing teams to score or it will be turned over.
Ok in that scenario those teams will just chip it around until the shot clock is up instead, that would mean most of match time would be wasted by teams chipping it around because they don't want to lose possession as a result they're outnumbered up field as a result of coaches snubbing the zone rule to have more numbers behind the ball.
Coaching panels have been doing this for more than a decade now. Enforcing zones by penalizing with a free will be reacted to by teams giving up a free to have more numbers in defence.
It won't work.