Hi. I had this idea after accidentally setting Germans against Germans in a Skirmish game. I'd already heard of the attempted assassination of Hitler but never knew how far the plans had extended - https://en.wikipedia.org/wiki/Operation_Valkyrie ... If Hitler had been assassinated then German units would have no doubt faced off against loyal SS units. So this would be an alternative history mod with maps made of locations where patriotic German units might have fought against SS (and other) units still loyal to Hitler even though he had been killed -
This action might have extended the war giving SS units still loyal to Hitler access to technologies that never made it into production at the time. Maybe jets and so forth. Renegade units (well the SS would have regarded them as "renegades") might have started getting supported by the allies or even by the Soviets if they wanted to see a government setup more sympathetic to their interests.
Doctrine trees might include propaganda elements on the renegades side emphasising their patriotic fight to save Germany from the SS. The SS side might include propaganda invented to inspire units after the death of Hitler. For example suggesting he was never assassinated and escaped to exile until control is regained. I suppose because of the similarity of the armies there might be cases where the other side knows the location of units or how certain weapons work and can develop a counter to them just because they are familiar with the German army.
So the entire scenario has a curiously compelling quality to it for me. But I don't know if it's enough to inspire entire modding teams.