On the Pilatus PC-12 I fly at work, the A.O.A indicator is on a short probe out ahead of the wing. The problem I could foresee on a model outside of the obvious electronic and mechanical complexity and the inherent weight of such a system is the need to be able to calibrate the system. You would have to do systematic testing, preferably in a wind tunnel with your exact wing section in order to establish your working range.This is just my opinion but an observant pilot can already develop a "feel" for the aircrafts angle of attack by carefully noting the direction the A/C centerline is pointing versus the direction of travel that the airplane is moving. It's been many years since I've inadvertently stalled or snapped in with a model if you develop this skill enough. Another useful technique is to take careful note of the stick position required to stall the aircraft. This is surprisingly uniform regardless of the speed of the model assuming you don't mess around with the rate switches on the transmitter too much.Just my 2 cents....