From the original question:
would ACM Peach make a good CAS
I think the answer would be yes, he could be a good CAS.
However, as others have said, it's never going to happen. Absolutely not for the reason that he isn't a pilot. Timing, circumstances, age etc. all play a part and in his case, his route upwards has followed an alternative plan.
As a light blue operator, my money would very much be on Adm Z for CDS. Timing and credentials are spot on. If we want to play the future CAS game, the focus should be on the current batch of thrusting, popular, competent and politically adept 2*'s with a view of 5-6 years from now.
Current CAS had all those attributes and was looking very well placed during his reign as AOC 2 Gp. Fortunately, those of us who had worked for him over the years and predicted bigger things were proved right.