This problem won’t be solved by lowering INPUT sensitivity.
Flaring most planes feels like balancing eggs (even after update 5). This should not be the case, as surface authority will decrease with lower speeds (lower dynamic air pressure). It should be possible to easily control a plane on a linear response curve!
So in my opinion the problem is of aerodynamic nature. Probably dynamic pressure being accounted for too aggressively on control surfaces. Or a problem with inertia.
In addition there might be several other aerodynamic aspects, contributing to the problem. Like too low drag (even with flaps out), too pronounced ground effect, etc.
So, please ASOBO, review the aerodynamics formulas! This probably needs a little more investigation.
Thanks for the great sim overall and all your effort in andvance!