Technically, I'd like to see less friction, so that the player's release and ability to adjust would become more important. I agree on juggernaut's argument, that the ball coverstocks should become more limited - either through harder materials or/and limits to the coverstocks' porosity/coefficient of friction. I feel the gap between the balls' potential and "lane reality" becoming bigger and bigger - we are already discussing how to tame down balls or make them useable at all through very weak setups. This is IMHO leading nowhere.
I do not see RG diffferential limits, as already set into action, to be a sustainable regulation measure. More oil would be another wish/option, but it is just the other side of the same thing.