I've been thinking about the stills style handgrip... its design may be perfect for stills mode, but nobody has been entirely convinced by its usability for motion. It's one of the first things people criticize of the new video DSLRs. Why should RED repeat their mistakes?
As an aside, in the famous exploded view:
...can some explain to me what the second, horizontally mounted handgrip is there for?
On the other hand, when I think of a handgrip designed for video that's been highly reviewed, I think of the EX1's rotable one. It allows you to change from high to normal to low mode of operation easily.
I think that RED should consider a version of this design for the DMSC system, if not as a substitution to their handgrip design, at least as an alternative. It should be robust, and easy to lock and unlock from a position.