I haven’t played 1942.2, but for me the famed viability of a KJF strategy is a huge draw over AA50 (which I have played).
In the Gamemaster edition, Revised*, AA50**, and 42 1st edition all require a KGF strategy for optimal Allied play. This makes 1942 2nd edition a very new experience to entice me with.
I have not played G40 2nd edition yet (only 1st edition). I understand that is also a KJF game, so for those of you who play that, perhaps KJF is less of a lure. I have also not played A&A: 1941, and have no idea as to the correct strategies there.
The minor victory scenario (8 cities) entailed a balanced Allied strategy for a strong defense in India. But I never tried a full blown KJF. I haven’t looked at that game for as long time, but I would tend to think Germany wins the game if the Allies go KJF in a minor victory setting.** I have only played the 1941 scenario (with NOs), and cannot attest to the other variations.