I still think the AUS is made to be cartoonishly right-wing in vanilla. At least swap up Long for someone who was less affiliated with progressives. And the devs are too dismissive of the Technocracy movement. But anyway.
At the time of the original Kr there was not enought info about long online, or even for other American populists, to the point that who was used as a American radical was the same as vanilla hearts of iron 2, Fritz Kuhn. The idea was to have one democratic, one far left and one fascist faction, and since Long was a southern populist they took him, to the point that Long was not a autdem, he was a pat aut. This was fixed on Hoi IV, but I agree it lacks content. The focus keep coming after the end of the civil war but about six events come out later and Long does in '52 (very early, he's not even 60 yet).