It was only possible to place the cannons in the existing wing outside the wheel wells, this would have created large moments of inertia, the roll would have dropped sharply.Agreed all the way.
The MG FFMs in the wings are the least problematic choice for a cannon setup, and by the time of the 109G, the 90 rd drum is in the play. By 1943(?), the belt-fed FFM is on use on the nightfighter Do 217s, so that is another thing to explore wrt. installation in the wing of a 109.
By the way, installing a droplet-shaped canopy on the Bf-109 would require a radical redesign of the fuselage's structural elements. Technologically, this would mean changing the manufacturing tools, which is a very expensive.
In my humble opinion, it was much easier to design a new aircraft than to redesign the Bf 109 - it had exhausted its modernization resources by 1944. The "Kurfürst" did not change the situation radically, the higher speed was achieved at the expense of climb rate and maneuverability if you consider the data of production aircraft, not prototypes.
Last edited: