The goal for any political party should be to (a) maximize voter participation while preventing vote meddling/ratfucking, thus closed primaries w/early voting are best (b) prevent party leaders (superdelegates) from publicly stating how they intend to vote (c) prevent supers from voting on the first ballot (d) but in the case of deadlock, then the supers should decide the nominee on the second and subsequent ballots instead of unknown party hacks and backroom dealers. (e) the supers should take into account how the first ballot went ie how the voters voted and the overall feel of how the primaries went.

Sanders does have valid beefs against the 2016 nominating process, but he clearly benefited from the highly undemocratic caucus system which has low turnout and is dominated by activists.

He also clearly benefitted from the fact that the media loves to hate Hillary, loves a horserace, and was just aching to build someone up like Sanders.. who did excite an element of the base (the left and youth) but not most of the base which heavily includes party loyalists, moderates, women, PoC, etc.

The issue is that Sanders is not a Democrat, and has always branded himself an Independent, and railed against Dems well before the Clintons came onto the scene and moved the party to the center (saving the party from itself, which had suffered numerous landslides due to the perception of being out of touch w/mainstream voters).

It is not just that Sanders is to the left - he is alt (independent) left, and not a left-liberal in the Dem tradition. Thus, he saw no need to build strong ties within the party, raise money for the party etc over his many years in politics. This means he had no support from party leaders when he needed it. ALL parties (including far left ones that Sanders may be more sympathetic to) work this way, by you know, politicking and building relationships.