So I do not own a Shaman, yet, which makes it hard for me to grasp it's finer points.
From looking at pictures, the height of the whole knuckle around the pivot seems taller than a PM2 and the stop pin seems to be moved.
The relationship of the blade height to the ricasso between the Shaman and the PM2 is also different. The PM2 plunges deeper whereas the Shaman is more shallow so as to achieve a taller blade.
On the Shaman, the nub of the ricasso meets your finger at the compression lock. If that was a sharpened edge, that would cut you. Now here is the point where everything has to be changed.
If the handle were taller and the compression lock was moved up to clear the sharpened edge, then dominoes start falling. This changes where the tab of the lock meets the blade, which changes the location of the stop pin, which then changes the point where it meets the blade when closed.
The blade could be made less tall, but that kind of defeats the point of the Shaman a little bit.
It's a circular problem that requires an entire redesign.
Going back to the core of the original post of the thread which was about achieving a knife that is free of snags at the heel...
On a PM2, because the sharpened edge is approximately level with the point where the stop pin rests while closed, none of the above clearance issues exist. To me the PM2 seems like a more natural platform, at least for the initial concept. The existing blade edge can simply be brought all the way back with a mini ricasso at the handle.
For the record, I'm very happy with the existing designs of the Shaman and PM2.
Because this topic seems to be fun, I took a PM2 and outlined the profile on paper, shown below.
I then erased the choil, took the FFG almost all the way back to the handle, and drew the mini ricasso. As you can see below, I expanded on the idea with two more drawings.
Obviously the G10 would have to get shaped a little differently around the shoulder of the handle. This moves finger location forward which then affects how your hand rides the center hump... so for now I set all that aside and focused on the blade.
From the point where the stop pin touches while closed, there would just be a small plateau to form the mini ricasso.
Like I said, I traced the PM2 first. When I redrew it, shown in the middle, I was very happy with the profile. It reminded me of the blade profile of my Manix 2, just a little bit less tall.
In order to achieve a taller blade, I just redrew it again, but taller on top. I think on that one, the thumb hole could be just a little smaller then what I drew.