Actually, I'd say that Kisshomaru Ueshiba, Gozo Shioda, Kenji Tomiki and Koichi Tohei are responsible for aikdio as we know it today. Ueshiba M. wasn't known for teaching things. He did something, and it was your job to figure it out. His students organized and codified the art, giving us the 4 very distinct branches of Aikido that most people know of: Aikikai, Yoshinkai, Shodokan, and Ki No Kenkyukai. These are really the creations of the first generation, not of the founder.