It was just based on your suggested very short flap wheel movement (implying that the force would go up). Some aircraft had heavy controls at speed because of short sticks and big surfaces.
Yes I am familiar with those. The servo tab also has the advantage of leverage.
Yes, but you are missing the essential point: Lowering flaps (or actuating any other control surface for that matter) does not in of itself create an aerodynamic force that counteracts it. All you are doing is increasing the curvature of the wing, and from that increased curvature you are increasing the angle of attack of the wing as well since the wing's chord line shifts with the lowering of the trailing edge. In the 109 this induces a nose down movement in the aircraft as the wing, now with its increased curvature, centers itself against the airflow.
The controls of many aircraft stiffen up at high speed because of shock waves forming over the control surfaces, usually bounced off of other parts of the aircraft. The P-38 suffered greatly from this due to its twin-boom tail. By design or luck, unlike many other WWII fighters the Spitfire was blessed with very light control forces even at extreme dive speeds. They were in fact considered dangerously light since pilots could easily over stress the aircraft.
