I have yet to see a fair breakdown of Sanders' proposals that wasn't later exposed to have connections to opposing interests. This analysis isn't terrible but it isn't quite fair...
In fact, I just looked this up and Wikipedia says, "In 2002, tax specialists who had served in the Ronald Reagan, George H.W. Bush, and Bill Clinton administrations established the Tax Policy Center to provide analysis of tax issues". Of course. All of those were corporatist administrations. That may not affect their analysis, but there is a real chance that it does. Simply being based in Washington means that this could be an establishment interpretation of his tax proposals.
As the Sanders' campaign pointed out in response to the TPC analysis, TPC framed their analysis in a vacuum without accounting for the overall savings most Americans would have. That seem like an easy way to misrepresent the entire point of his tax policy, which is part of a bigger picture to bring money back to the lower and middle classes... Money that should have been going in their direction to begin with. The Vox article doesn't really come off that negatively. But nevertheless, it is conveyed out of context. What use does the average American have for a tax analysis without the appropriate context, when it is really part of a bigger picture?
I have learned better than to suspend all disbelief with this kind of news story. The media and "think tanks" have not been conveying the whole truth during this election.
And my opinion is that the higher tax brackets should have been paying more to begin with, so I can't really sympathize with them or think of it as a loss. The system was skewed in their favor, and it needs to be rebalanced. Unless you disagree with taxation altogether, it has its purpose and it has not been doing its job supporting the lower and middle class.