The weight of the flipper bat isn't meaningless when it comes to the speed of returning the flipper back down. The return spring will be able to reset a lighter flipper faster than a heavier one. Giving you a more responsive flipper, similarly to the way a race car suspension works best when it has the lightest unsprung mass. Ball speed/control would be more a factor of coil strength and flipper rubber?

I was just imagining where we would be if pinball was as popular as golf is. Would there be revolutions in flipper designs with different materials and weight distributions as they have with golf clubs... Titanium flipper bats with adjustable weights?