I have a few disagreements with what you're saying.

You may ultimately disagree with the belief that Bernie Sanders would have been a stronger candidate than Hillary Clinton, but your disagreement needs to be based on something more concrete than, "he's too left wing".

It's not that, though. Look at his track record: what good did he ever do for the poor and for minorities? When did he ever compromise? How did we know that he was going to compromise or get stuff done, given that to get stuff done you actually need to be able to call in favors and have a good relationship with people in congress, and given that he's almost literally the left-wing Ted Cruz?

For the love of god, stop calling Bernie Sanders a socialist

Okay, fair point. The policies he proposes aren't exactly socialist. On the other hand, has he ever disavowed the straight-up socialism he had in his early days?

Most importantly, acknowledge that progressives have legitimate grievances with establishment Democrats

Social democracy was the defining American political ideology from FDR to Jimmy Carter, and it was ultimately abandoned not because it had empirically failed, but because the white working class decided that they hated black people more than they liked the benefits of a welfare state. American progressives believe that their party and their allies have abandoned them, and they're not entirely wrong about that.

Citation needed.

The modern Democratic Party isn't just dominated by neoliberals, it's pretty much exclusively run by neoliberals.

Sometimes I think people think that parties are way more centralized than they really are, then again my civics textbook is around 7 years out of date so I may be wrong on this one. Point being, can I get a source for that?

Do you know why progressives got so angry when Perez became the DNC chair? It's not just because of loyalty games, although those played a part - it was because it was part of a general pattern of Democratic leadership going out of its way to exclude progressives from leadership positions.

Again, Democratic leadership holds less power than you think. There's practically 50 different Democratic parties, and the leadership has to handle the concerns of all the factions in the huge tent to stay in power.