My Dream team for Sentai would probally have to be Yoji Enokido (FLCL), Kazuki Nakashima (Gurren Lagann), and Masami Kurumada (Saint Seiya). Why? I loved FLCL and Enokido knows how to write really good stories with a flare of crazyness here and there. For Nakashima, it's pretty much the same reason that Ryou has. Finally, I'd add Kurumada to this because he can write good stories along with producing some great art.
I would have to agree with Ryou on having Chiaki J. Konaka write for a Rider Series but, if I had to say someone else, it would be Stan Lee. Why Stan "The Man"? Well I've kinda figured that if you ever had him do a rider series, it would probally go back to it's Showa roots. Cause in retrospective, Ozamu Tezuka was the Japanese Walt Disney while Shotaro Ishinomori was the Japanese Stan Lee. Thus resulting in high amounts of awesomeness