News flash.Smaller=Lighter.
Yoda could move quicker than Sidious.
This is DE Sidious, who can move faster than the eye can see. I'd say that's faster than Yoda.
Also, for all of you out there wondering, yes, Darth Yoda could defeat Darth Sidious.
RotS Sidious? Definately. DE Sidious? He's got a shot.
Yoda in a dark form would receive an amplified boost of power - enough to fill the miniscule power gap that he and Sidious seemed to have.
There is a big power gap between Yoda and DE Sidious.
Get it? It would more than bridge his power to Sidious and make him likely significantly more powerful than him, even in the area of generating Dark side techniques like Force Lightning.
This is DE Sidious. Not RotS Sidious.