+1. Shingen was a great warrior and leader of men but he wasn't, per se, a conquerer in the strictest sense. I mean, only as much as every Daimyo at the time was. Shingen himself seems (from what reading I've done) to have been more concerned with sort of a moment-by-moment state of his kingdom than a grand vision of uniting all Japan.

Nobunaga...eh, I think others feared him but I still don't see him having the same time of personal charisma as Napolean. For that I'd stick with Hideyoshi.