My guess would be an affordable cinelens line.
nah, no way
My guess would be an affordable cinelens line.
yeah comes directly after an affordable lamborghini on my list... 
Ahahaha, I know it is a bold guess, but apart from a camera, lenses are one of the only things all videographers use. I don't really see what "revolution" could be made for lightening or sound recording, and gyros are not used in all styles of video. However, there actually exist a affordable cinelens line, made by Samyang.
Another thing I can think of would be some sort of Canon-made Metabone Speed Booster. It is some sort of reverse teleconverter, that enable the use of FF lens on smaller sensors with there native focal length and add one f-stop by shrinking the image circle it produce. However, I really don't see Canon, or any other major camera maker as a matter of fact, make such a product, as it would certainly hurt their full-frame sell, in favor of lower-end bodies. Moreover, they would have to find a way to work around the required lens to sensor distance to make it work.