It's not really needed IMHO. Why? This focal length range is fairly short, the lens is already very fast at a constant 2.8 and adding VR would only push the price of this lens even further out of reach of most consumers.
Don't forget that VR is only useful for operator motion not subject motion. Therefore I would humbly suggest that with today's high ISO capable cameras that someone should be able to find a decent enough shutter speed to handhold a shot at f/2.8 with an ISO up to say 3200 - no VR needed. Frankly what most people who think that VR is necessary, in reality simply need to put more time into proper hand holding technique.
VR is a nice feature to have in some instances but it is far from necessary on most lenses. Give me a fast constant aperture lens with any of the newer, high ISO capable cameras and I'm a happy guy!