In the post-Watergate reforms of the 1970s both parties adopted nominating systems that allocate delegates according to population in large part but not exclusively. Famously or notoriously they also created super-delegates, composed mostly of elected officials, who are thought to be likely to choose the candidate who seems ideal at the end of the long primary season. Presumably early voters or poorly informed voters in some states might have erred in the process. 

This anti-democratic measure is under attack. Primary voters in both parties want to choose directly the nominee.

It follows that the same voters, by far the most likely to vote in the general, also support the notion that the popular vote should directly choose the president in the general election.

If the nominee needed to win the national popular vote to win the general election, it seems likely that the nominating process would become more democratic, and the number of super-delegates would diminish. It would make sense for any national party to use the nominating process as a test run to determine vote getting capability in every state. More than that, the vote getting would try out themes, policy positions, and arguments in advance of the general election. In short, the whole process from soup to nuts would probably become more democratic with a little "d."