I'm surprised the 24-70 does not have IS. To get IS in an L zoom you've got to go to the 28-300 or 70-200 lenses. .
Don't forget the 24-105 has IS.
I am shocked the new 24-70 does not have IS. Looks like Tamron beat them to it with their new Tamron 24-70mm f/2.8 Di VC USD. I am interested in the IQ of this lens