If this doesn't incorporate a brass deflecting design, I don't see it being widely adapted.
If you can put a lip that deflects brass and keep it inexpensive while aesthetically pleasing, then you'll sell a truckload.
Currently there are other products that protect the stock from ejecting brass - at very reasonable prices.
The two products that deflects brass are the manticore brass buster and the corvus defensio brass deflector. The manticore product is cheaply priced and aesthetically a disaster (in my opinion). The corvus product is insanely expensive, must be imported, and there are reports of its failure.
Then you have the Steyr brass catchers which can act as a deflector as well, but those are even more expensive than corvus' offering, and only work with certain AUG receiver models - and may require modifications...
If you build it, they will come.