Mechanization hurts COIN forces

[William F. Owen]

Wilf; 75mm HE was adequate in most WW2 combat (there was a desire for bigger bang and specialist assault vehicles with ~150mm guns, though).

Yep. Concur. 75mm CN-75 stayed viable well into the 1960's and if you could take a CN-75 (copy of Kwk-42) you could probably take a 105mm. The balance is always for HE and AP performance. L7 105mm is and was an outstanding tank gun, but it does require a good chassis.

Something like the 76mm low-pressure L-23 is probably all you need for fighting the Taliban.