Hell, I don’t usually use search function, but I found that having 1Tb of music collections and the needs to specifically go for some tracks is a little worrisome...
I am almost sure that the successor of Signature series will have more power output. This was a problem that plague the S-Master for so many years and through many generations of modern Walkman. It is now solved with either Active Ground control from TA ZH1ES or using GAN FET such as SAZ1
I think signature series may no longer have copper and gold plated chassis ? I could be wrong, but judging by the technologies within DMP Z1. There are better ways to get the Sony house sound without the expensive, exotic, Fancy Full OFC Goldplated chassis. One example is to utilize the Inner frame constructions as you can see on many Walkman including 1A/Z
I am almost sure that it would still have walkmanOS.