I would go for a limit on weight and leave the batmakers to the rest. Even that is a tricky one as many pros have lightweight clefts and many weigh 2'9/10. However, limiting weight to 2'10, for example, would at least restrict off centre hitting by those favouring huge willow eg. gayle . It also misses the point that Pros are so well drilled that they don't hit many shots off centre like us village hacks, so the edges play less part in their games.
They could do worse than increase boundary sizes, bat technology has made them easier to clear but the boundaries have come in, not out!