I do believe a shorter shock can make a difference in feeling but not because the lower CG. Xray did make the mistake on the RX8 I believe the 2013 model which did not help to make the car better so new longers shocks were designed for the next year model
In the 1/8 onroad racing we do see more and more lower CG placed cooling heads giving temperature issues so from time to time you see drivers replacing the head by a normal higher version w/o needing to change the setup because the higer CG. And then we are talking about a 10 gram high in the sky and not a 5 gram already arround roll center.
But I trully believe most of these yearly changes and all the technical bullsh*t stories are not to make the car better for more than 90% of the drivers who can not make an advantage out of it but more to give a reason to them to buy the new car anyway.
Mugen on the other hand dares to do 3 years with a car with only some options in that period. And if possible the next car is based on the same platform so only an upgrade kit is needed.