The servo throw is not linear due to the circular motion... TRUE!! ... but assuming the horn is a similiar length to the servo arm, the ratio of Servo Deflection-to-Control surface deflection will still be (nearly) linear. I am currently flying planes utilizing plus/minus 45 degrees of control throw... so the ratio is very nearly 1-to-1... as the arm gets shorter, and/or the horn gets longer, the linearity dissappears.
ORIGINAL: EXCAP232
Most newcomers to expo feel the same way. In reality a servo with a rotary output moves more around center than it does near the ends in a linear fashion. As the servo reaches the end of travel it moves more side to side than it does in the direction of the control surface. Still you aren't crazy. It probably does feel "good" as that is what you have become accustomed to. Small inputs are needed more around neutral for precise control. I have had many students say the same thing only to come back the next season and say they now enjoy and use expo. Give it a try as you will most likely become accostomed to the new found tool.
EXCAP232