Democratic Party is still sort of garbage but Bernie isn't a panacea. Corbyn showed the potential behind energizing a large youth vote behind a progressive/leftist platform with a real vision for the future, and that's something Democrats need to seriously look at going into the 2018 and 2020 elections. That's a good strategy for Democrats to take in a lot of places. Overall, though, if they take back a majority in the House or Senate, they're going to have to bring along blue dogs and suburban neoliberal democrats with them.
e: they're also two distinct political systems with substantially different structures and political histories and cultures. I don't think Corbyn's platform would work too well in much of the US.
e2: I think more centrist dems have a decent counterpoint, too, when you look at France. Corbyn had a very strong showing, but ultimately, he didn't win. Macron not only won the Presidency, his newly created political party took a large majority of the parliament.