Al Gore was sullied by association with the Clinton whitehouse, ultimately this may have cost him the presidency. BO should not chance this as VP under HRC. He'd be taking a large risk just having her as his VP.
As soon as a Clinton is on the Fall democratic ticket, the Republican sewage will start to flow at full volume. They are sitting on the Giustra-Kazakhstan affair Clinton Campaign Bought and Paid for, there's a new item that's emerged from a right-wing canadian website Former Clinton Official Named as Russian Dupe, not to mention all the old stuff A Clinton Scandal Primer. Google 'Clinton scandal' if you've the time. What new muck might occur in the future, for "a tiger can't change it's stripes"?
BO would have to vet the Clinton's very carefully before taking HRC on as VP. Once in the whitehouse he'd have to keep a very close watch at least on Bill. BO should not run as HRC's VP.