[2023] why M11/39 is improve light tank in 1939 scenario?

Reni Malaj said: The Bf 110 wasnt a heavy fighter per se. It had a slim fuselage and rather short wings. The plane was comperable in size to the 109. It came from german experimentation with the Schnellbomber and later Zerstörer program. Both gave birth to relatively light and fast combat aircraft. Another product of this line of thinking, the Do 17 is also ingame a light airframe. They stand in contrast to larger planes like the Ju 88 series, Do 217, Fw 200 which were propper long range planes.
All of this does not come without its issues. The Sprites and Models are assigned in the designer according to the old tech tree where the roles were set more arbitrarly. However im hopeful that the situation will improve with time.

Unfortunately I have to contradict you on this. The Bf-110 Zerstörer (the Bf-110 IS the actual Zerstörer) is significantly larger than the Bf-109 in addition to being a twin engine fighter and more in line in size with comparable heavy fighters like the Bristol Beaufighter and the P-38 Lightning.

Also the Bf-110 according to HoI IV localisation files is still categorized as Heavy Fighter thus requiring a medium airframe.