Could the stick position be used as a Angle of Attack indicator?
For a given set of configuration parameters, CG, weight, power, G loading, you could theoretically use stick position as an approaching stall indication.  Problem is, the actual location would vary with all those parameters, so if you had a stall indicator device that was measuring and displaying stick position, you would constantly have to vary the calibration with power setting, flap position, G load, all up weight, and center of gravity.

So, take the apparatus you would have developed to go under the floor to measure where the stick is at, and move it out to the wing with a vane that gets blown on in the clean air flow, have THAT drive your indicator, and voila!  No need to adjust for any configuration variables and you know exactly where you stand relative to stall at all times and in all flight regimes.