ORIGINAL: ram3500-RCU
I certainly agree that the geometry of the physical connections is very important. While a push-rod connected more closely to the output shaft of the servo will mean more travel on the stick for the same deflection, this is nothing like the 'soft' feel that expo gives you in the center of the stick, for movement is 'exponential' not linear. I think these subjects are apples and oranges here. Both great subjects to explore, but completely different.
The reason for going "in" on the servo wheel toward the shaft is to maximize torque. This is also true for being "out" at the control surface horn. While there maybe some "expo" realized here, torque is the main reason for doing this. Granted, this will not always give the desired amount of control movement, so we tend to be other positions to get what we need.