I'm a big fan of 1up's "The 1up Show." Video reviews done by the likes of GameSpot and IGN are pretty bland and boring, but given the proper length, style and content, video reviews can rule pretty hard.
I guess the biggest hurdle would be finding someone with the time and talent to give video reviews more flavor than the tried and true "guy-talking-to-webcam."
Even then, they should only be supplementary. Text reviews are the meat and potatoes of games journalism and I can think of a few places where short attention spanned chumps can go if they can't deal with it.
If anything, GR should take a stab at podcasting before going in to something as involved as video.