Let's review the revision list for a moment
We start off with this as your question (emphasis mine)
Have there been any safeguards or special rule changes within the DNC to prevent a rigged or unfair primary process as with what happened to Bernie Sanders in the last election cycle?
This isn't a good faith question because you're asserting that the process was rigged or unfair. Now, it might not have seemed fair to Mr Sanders and his following (and indeed, it's been revealed that there was bias behind the scenes), but those were the DNC rules at the time. So it's not good faith to assert that it was rigged or unfair, because Mr. Sanders himself agreed to run underneath them (as opposed to a third party bid). You're basically asking a "Does your mother know you're stupid?" type of question (where there is no good answer).
We then get into a rollback war with grovkin, who made an inappropriate edit by adding all sorts of supporting points to the bad faith assertion about the process.
The current question still asserts it's unfair, and you'll note that the answers have descended into defending or decrying the assertion that it was "rigged" or "unfair". The accepted answer, for instance, spends 3/4 of its length defending the "rigged" assertion. Only the last paragraph attempts to answer the "what has changed?" question (which is on-topic). Attempting a rework now would invalidate the answers, and I'm of the opinion that it should be deleted and re-asked without the "rigged" assertion. Contrast your question with this one that merely asks why the DNC was biased. It avoids assertions entirely and simply seeks to understand the email dump.