The analyst in me is well aware that nothing has changed; Hillary Clinton remains the odds-on favorite to win the Democratic nomination, and if so will likely be elected president. I would say the likelihood of that happening, right now, stands at about 75% But it's a long way to November 8th, 2016 (1 year, 6 months, 7 days to be precise, as of this writing) and a lot can change. She seemed like a shoo-in in '07, too, and then this Obama guy came along...
I'm not saying Bernie Sanders is going to take off like Obama in '08, although that would be glorious. But he could be a big enough factor to be a thorn in her side. He will win the New Hampshire primary almost by default (he is from neighboring Vermont, after all), which means Hillary Clinton is now in the position that she must win Iowa or else run the risk of losing both of the first two major Democratic contests. And remember, Iowa is a caucus; those tend to favor more liberal candidates. There is a realistic chance that Bernie Sanders could win both Iowa and New Hampshire, and then suddenly who doesn't look quite so crazy a proposition any more? Nothing succeeds like success.
Again, being realistic, I don't expect this will happen. Even if Bernie wins the first two contests (which I think is a real possibility), Hillary would win South Carolina (the third contest) and then go on to win the lion's share of the delegates on Super Tuesday and beyond. Losing the first two will be an embarrassment in the long run. But yeah, in the short run I can see Bernie having a moment. And as I have been saying, his presence will force the discussion to include stuff that Wall Street pols like the Clintons don't want to talk about. It will force her to the left. That, ultimately, will be Bernie's role in all of this.
But a boy can dream...