It is becoming increasingly popular to bash superdelegates in recent days, for several obvious reasons. Most fundamentally, the fact that the pledged delegates are beginning to hint at one story, while the superdelegates currently are on the opposite side inspires people in a fit of democratic fervor to speak out against these tyrants (okay, no one's called them "tyrants" ...yet). More than just a few people have declared their lack of faith in the SDs, including a prominent SD herself.

If we could just put the torches and pitchforks down for a brief moment, I'd like to propose a few hypotheticals in which we'd be in real trouble without superdelegates.
1. The Ron Paul: If candidate x, running as a Democrat has a lot of ideas that critically undercut the party's platform, it is clearly in the party's interest to mobilize against that candidate. After all, the candidate owes at least some of his support and his visibility to his party affiliation, and should not be able to ride those coattails to cut off the party at the knees.
2. Late scandal: Pledged delegates are decided at caucuses and primaries months before the national convention, and legally bound in their vote. There are any number of scandals that could become known after the delegates from the voting have already been pledged. Without superdelegates, it would be impossible to insure the Democrats don't walk into the general with a candidate that is going down in flames. Imagine trying to rally the party around an indicted candidate.
3. Accountability: Consider the possibility of a tight election in the final states to vote. 11th hour tactics crossing all reasonable bounds of ethics could be employed. The mere existence of superdelegates as a final after-the-primaries primary discourages such self-destructive behavior.
4. Last minute rebellion against the party: This one is barely even hypothetical. Consider if Clinton strongarmed the seating of Michigan and Florida delegates to tip the votes her way while the DNC was still vigorously opposed to it. The superdelegates again offer a check against such party-endangering tactics.

It's useful to take a step back and evaluate what the likely priorities are of these superdelegates. They are elected democrats, and they are the quiet machinery of the democratic party itself. A few individuals back one candidate or another for power in a possible future administration, or out of loyalty for favors done in the past, but this is the vast, vast minority. On the whole, there is likely no group of people that is as devoted to the idea of advancing the Democratic party than these superdelegates. These conspiracy theories of SDs quietly biding their time in hopes of being able to subvert the will of the Democratic voters are just that - Conspiracy Theories.