Seriously? Windu created form 7, vapaad, accessible pretty much only to him (on the light side)because he partially used the dark side. He was only matched by yoda and Anakin. The reason he died is because Sideous was the most powerful sith to ever exist (he literally created Anakin), and Anakin had potential to best that before he became a cyborg.
/endrant starwars nerd out