Breaking up the banks means splitting them up into separate entities, not killing them. I don't see how that creates an economic impact.
And he has lots of differences with Clinton. He's for single payer healthcare while Hillary wants to keep with Obamacare, and he's for free college while Hillary has an overly complicated plan to create debt free college.
There's also issues like the TPP, where Sanders disagrees with it at the core, while Hillary wants Obama to get a better deal, and Citizen's United where Sanders has pledged to only nominate justices that would overturn the ruling, while Hillary wants to do it through a constitutional amendment that has no chance of ever happening anytime during her presidency.
I think there's also something to be said about general focus, like how Hillary mostly focuses on gender inequality while Sanders mostly focuses on inequality between the rich and the poor.
I think you have to not be paying attention if you really think this. Even outside the campaign trail, you need to look at how often Sanders, Warren, Brown, and Franken disagree with Obama, and I don't think it's a big leap to say Hillary is going to align more with Obama on those issues that don't get as much attention, like finance regulation.