It's feasible for SJ since everything will be redone; ground textures, vegetation and buildings. But SJ has a much smaller focus and redoing all the cultures to a satisfying standard will be a monstrous task indeed. Rescaling buildings won't be much of an issue, but redoing the city maps will be. Sengoku Jidai is focusing on MP gamers and to have 4vs4s without armies lined up from red line to red line something needed to be done. For a single player mod I doubt that it's worth the trouble.