Just my thoughts:
1. I don't see an advantage over a regular pocket holster.
I've used a pocket holster for my LCR for months now, in a variety of different pants/shorts (tight jeans, loose jeans, cargo pants, slacks, suit pants, cargo shorts, etc.) and have never had an issue with shifting. The grip is always where I can get it easily.
2. Different pants/shorts have different pocket lengths, and distances from belt.
With a shallow pocket close to the belt line, the suspension strap will buckle and interfere with the draw. With a deep pocket further away from the belt line, the top of the gun/holster could become visible in the top of the pocket. In other words, the strap will need to be adjustable, but without adding too much bulk or extra strap to get in the way.
3. A phone or whatever it is attached to the strap to hide will will get in the way of the draw.
In order to get to your gun, you will likely have to manuver around the phone. Going into your pocket will be slower. The gun will also have something additional it could catch on, dangerously stalling your draw. This is all hypothetical, but something to think about.
For me, it boils down to my #1 point. I just don't see the advantage over a regular pocket holster that is more simple, and likely less expensive (my DeSantis Nemesis, I got for around $15, and it works wonderfully). When you add the disadvantages of #2 and #3, I just can't see what makes it better. Let me address your concerns:
1. The holster needed to be suspended on my belt. I didn't want the XDS sitting in the bottom of my pocket where it could
get out of position when needed. I also didn't want the wear in the pockets on my WallyWorld cheap-o pants.
Most pocket holsters are stable and won't move around much. Even if they shift a bit, it's nearly impossible for the grip to get into a position that you won't be able to grab it. What holsters have you used that had this problem?
2. The holster needed to have a minimal print on the outside. What did show needed to be seen as a phone, iPod, digital
tablet, wallet, or something other than a pistol.
This is solved with a regular pocket holster. Something on that strap, as I mentioned above, will more than likely get in the way. Would you plan on adding an actual phone (or iPod, wallet, whatever) holder, to the holster, or would it be a faux object? Keeping in mind that objects outside the belt like that are targets for pick pockets. Also keeping in mind that the faux objects usually looks just like that, faux objects. There was a tuckable holster that I don't know if it's made anymore, but it had a faux pager that looked fake. It drew more attention than anything. (Here's the holster: http://www.pagerpal.com/pager.asp
3. The holster strap suspension needed to give the appearance of being a wallet or other benign object hanging from my
4. Lastly, the holster strap needed to flex enough to accommodate a sitting position.
Pocket holsters are notoriously difficult to draw while seated. Your holster makes it even harder by packing the top of the pocket with a strap that makes it even more difficult.
Now, having said all that, if you have tried some different styles of pocket holders and they don't work for you, and this actually works for you, then by all means. If you go forward, I would stay away from leather, at least for the strap. You'll want something that can flex and move around a bit, plus leather will not be as easy to adjust. Nylon webbing would seem to be a better material.
I'd like to see this thing in action, and maybe a better explanation of the problem it's solving. I haven't had an issue with a pocket holster shifting enough to make it hard to draw, but maybe you have? I don't mean to be negative, but these are just some of the issues I see with this particular holster.