No one ever said the narrow engine would magically transform the bike but it would give a much larger amount of adjustability.
Go look at bike specs from 990 to now and tell me which bike still has a long wheelbase and low CG, then tell me which bike is shity in the corners and in agility change of direction. If the word of Aprillia, Honda, Yamaha, and Suzuki who have all said the 90 degree engine is not optimal because of balance and the longer wheelbase required to fit the engine than I don't know what else to say to you. It seems your problem is with the yellow koolaid drinkers instead of Ducati who haven't delivered the one thing at a time as you say. The crew asked for the engine to be changed in January and it still hasn't been done. Back to the wheel base, maybe this simple picture will help you understand why a smaller engine is much easier to package and get a smaller wheelbase out of.