Simpler solution: Add MBA with 15" screen. Retina display only on MBP models. Nice stair step pricing and less confusing overlap. Either slimmer and lighter

Simpler solution: Add MBA with 15" screen. Retina display only on MBP models. Nice stair step pricing and less confusing overlap. Either slimmer and lighter or faster and better graphics. No 11" MBP because people demanding nice graphics want bigger displays. No 17" MBA b/c thin and huge doesn't appeal to anyone.