I've got a .40 PPS Classic, and while the recoil never bothered me (cut my teeth on .44mag and .45 Colt) I did order a DPM recoil reducing spring kit.
Eventually, a series of choices led me to 9mm variants of my PPQ and then PPS, so I kinda gravitated towards that, as it's easier to get back on target, not to mention an extra round (or three, in regards to the PPQ..)
In my case, the DPM kit wasn't needed, and helped....somewhat, though it wasn't a problem for me. I'm 42 now, I was 36 when I got the .40 PPS.....not like my hands are weak or crippled...for now, anyway..
That said, I'd find it unlikely that we'll see a PPS that starts with a ".4" as it's caliber. Unless the brass in Germany decided there is enough of a demand for a .45 PPS. Kinda gets back to the more isn't always better thought process. I also had an XD-S .45 before I got my 9mm PPS...in fact, traded one of them for it.
Hated the feel, and the trigger. Solid gun, even pre-recall. Never had an issue. Shot a box of 165gr +p through it....worst 20 rounds I ever fired. Awful.
I'll stick with 9mm. I'm willing to try that there new PPQ SF in 10mm, should Walther smile down upon us with such a beast..