I personally think that a Hellcat Pro-ish sized pistol, with a capacity of 10+1 and in .45 ACP, would be the most perfect gun to make. It could also probably be offered in 10mm as well.
Any chance Springfield?
Right now, there are few guns to fill that place; the XDM 45C is 9+1, and the grip is too short. The Glock 30 is fat in all dimensions, and reloads are slow because of the large magazine basepad. Really, only the original XD45 Compact checks all of the boxes for me, but a Hellcat Pro would be significantly better.