I'm not sure I want Hillary to be POTUS. She's done a bang-up job as Secretary of State, but she's a political lightning-rod. Too much Bubba-era baggage in the hands of right-wing propagandists. Who wants Vince Foster and Rose Law Firm billing records to be thrown against the video wall every day for two years before any votes are cast?
Michelle is a political dream. She does the crowd-control thing even better than Barack does. But she's very light on actual policymaking experience, and super-vulnerable there.
So Warren is still the top get. I think she'd rule the primaries and then she'd stuff the "socialist" taunts back into the taunters' faces during the general, same as she sent Scott Brown packing.
And if the GOP thinks they're going to win by gaining minority or women's votes by running a woman or minority, then they don't understand their base at all. It'd fracture even before the first primary, and then it'd be a real 3-party race, and the Dems would completely own the plurality in the general.
Pencil in Democratic Party presidents until 2025, and plan accordingly.
P.S. America elected a black man President, _again_. Got to love a country that does that after living through its history.