These new IS primes are geared towards video. However, if the 35mm f/2 IS was $800 or less, I would snatch one up in a heartbeat. That is of course assuming the following:
1)Its a true USM motor
2)Its very sharp wide open
3)IQ is better than the current cheap prime lineup
I think that would make it a nice alternative to the 35 f/1.4L. $600 less, probably much more compact, and with IS.
Right now Canons offering in that Focal length is pretty slack. The 35 f/2 is noisy,slow, and flimsy. The 28mm f/1.8 has so-so IQ. Sigma is rumoring a 35mm f/1.8 so this new Canon version would probably be in the price range to compete against that as well.