During every season, we use an equation so the output of the joysticks followed a cubic function. This allowed for finer control at lower speeds without using a piecewise function or sacrificing max/min speed. We also experimented with quadratic, and quartic, but our driver liked cubic the best.
For Turning Point we added some more driver assists. The first was slowing down turns when the joysticks were within a certain range. This helped our driver could aim more precisely, without hindering regular point turns. Another assist was equalizing the speed of both sides when the joysticks were within a certain range of each other. That would help drive straight even if the drivers joysticks were not perfectly aligned. Both of these assists were very specific to improving aim during Turning Point game play. You should analyze the current game and see if there are assists the driver would need in certain scenarios. These assists can help drive the robot more efficiently.