You overlooked “lightweight and air-dropped” as being two of the requirements of the Wiesel. Panther & Tiger tanks were definitely NOT “air-droppable” or planned for it. The Wiesel was used as a reconnaissance vehicle for Leopard tank units. One recon version carried a 20mm cannon. It was also used by their artillery forward observers, at the time when I was running around Germany in my M-151 jeep as my Forward Observer’s vehicle. There were other variants designed as light anti-tank missile (TOW, HOT & Milan) and anti-aircraft missile (Stinger) platforms.
See: https://en.wikipedia.org/wiki/Wiesel_AWC
That 20mm weapon the Germans use is not a joke.High rate of fire and very high muzzle velocity.

Imagine the Luftwaffe doing that with a Me 323 Gigant and a Tiger tank:

It would have been epic, succeed or fail.
“Everything is air-droppable at least once.” Maxim 11 of the 70 Maxims of Maximally Effective Mercenaries. Schlock Mercenary, for those who are unaware.... ;-)