The very early 109s had very reasonable control forces and harmony, but as the series' speeds increased the ailerons began to lose effectiveness culminating in the higher speeds of the E model. The F had a redesigned wing that included completely new ailerons (and flaps) to improve high speed aileron response and eliminating the wing guns improved roll response further. Unfortunately for the 109, the new F model wing was found to be a pinch too small in total area so elliptical wing tips were added to solve that problem while negatively impacting the newly improved roll response ... oh, well. The K model was originally intended to have boost tabs (also known as flettner or servo tabs) on the ailerons but, although boost tab equipped ailerons were produced in very small numbers and installed on some K's* the tabs were riveted in place to inactivate them.
*I have a copy of a G10 factory drawing that shows the deflection angles for these ailerons as well as the boost tabs but there doesn't seem to be any evidence that any G10s had them installed, activated or not.