It would be nice to have a president pushing for higher taxes on the wealthy, but wait a minute, it's Congress that levies taxes. The president can only recommend, as far as I know from what the constitution prescribes. Congress passes the tax laws. Who gets into Congress is important.
Bernie Sanders had the strongest positions for taxing the wealthy, but what could he do without Congress? Now that it doesn't look like he will get the Democratic Party nomination, the energy behind him should really be directed at changing Congress. I believe Hillary Clinton would make a good president even though she is more of a middle ground compromise than Bernie Sanders. A lot does depend on who is in Congress. It may be less glamorous than the presidential race, but Bernie's supporters ought to be thinking about Congressional races also.