I think the pendulum swings here once again. Two years is a long time in politics and as I look at the world's many foreign policy challenges and war weariness in the country, America will look for what they see as someone able to skillfully keep the peace. That bodes well for both Clinton and Biden obviously. America always wants an inspirational leader and 2016 will demand that. There is no mood in America for a Mr. FixIt who the public won't instinctively trust, and who can blame them. Divisiveness is on its last gasp now, and will be dead in January. It the republicans persist with obstruction the party will simply implode until somebody grasps the greatestness of Theodore Roosevelt. Only this kind of republican will America ever trust again. Ironically, eventually even Teddy left his own disconnected party.
So its premature to speculate on Democratic 2016 motives.