Honestly, I don't get the criticism of superdelegates. While I agree that most of the delegates should be chosen through the primary and caucus process, I don't think that it's unfair to let elected officials who are party leaders have a say as well. (And their votes should be equal to a pledged delegate, not greater). Plus, superdelegates can change their vote before the convention, and have in the past, especially when it became clear who the presumptive nominee would be.
It's similar to the argument against the Electoral College, but this is in the party so it's not like a general election. I think they don't want a repeat of 1968 in the Democrat side, or what might happen this year at the RNC. But, superdelegates switched from Hillary in 2008, they could again.