When I moved from the old cakewalk Pro 8 (in my case) to the newer MC series, I found that many things had changed. The old things and ways I used to use were outdated. New things were in MC that were not in the pro series.
I started to learn the new stuff and have never wanted to go back to the pro series way of working.
As far as "will the PSM work in MC? I have no clue. Since it is a midi device and it worked in the pro series it seems reasonable that it might work in the newer DAW's.
If no one here has a definitive answer, email support and ask them what, if any of the cake products would support it.
In the old Pro series I used a mixer and a few other things that were outboard hardware. In MC I only use a quality interface (less cost then a mixer) and all my recording is done direct input (mic & guitars) or midi in to the interface. Have a listen to the music I record in this manner on my web site.