Yeah the 24-70 took the place of the 28-70 but Canon just revamped both the 24-70 and the 70-200 2.8 IS. Both are supposed be much sharper especially at the long end of the zoom but both cost much more as well.
Depending on what type of photography you do the MK1 versions are still pretty good. Does the 7D have Micro Focus adjustments? That will help dial in each lens. Something I really wish I had on my bodies.