It’s the vision that matters. When we elect a president we elect an entire administration including presidential advisers, the White House staff, and the Cabinet.
Immanuel Wallerstein, in his October 2015 article The Resurgence of the World Left? says that
the real battle [facing the world is] the one concerning the direction of the transformation of the capitalist world-system into a new world-system (or systems). That battle is between those who want a new system that may be even worse than the present one and one that will be substantially better.Wallerstein asserts that the apparent leftward swing appears to obscure this real battle. Perhaps so, but I think it depends on who the observer is. As the US version of the Internationale puts it, "'Tis the final conflict," and it is a real conflict of and over real interests -- perhaps even a genuinely final conflict considering the climate peril. Each step in the struggle is important.
Bernie keeps reminding us of the obscene economic inequality in the US (not to mention the world.) The people at the top, the 1%, the oligarchy -- call them what you will -- are working overtime to make sure any new system preserves their privilege and dominance.
Bernie's vision is in the direction of a system that is substantially better for the majority of people. I think he can help us move in that direction. Hillary, a neo-liberal, is bound up with the oligarchy. Her answer on fracking in the Flint debate showed how beholden to the oligarchy she is. She can’t say no to fracking. Or to Wall Street.
Both Bernie and Hillary are principled people. I prefer his principles.