Clinton was the obvious choice, but was Clinton the safe choice? Her problems with likeability, especially among independents were known going into the campaign. She was the 'next in line' and had the support of the party leadership, that's really the only reason she won. Sanders is not part of the party leadership but ran under Dem party for exposure and he certainly showed the weakness of her position among the young Dems.

Hindsight is always 20/20, but the Dems could have benefited from a proper vetting of candidates, for instance if Biden had entered the race. Another way of putting it is this, competition during the primaries keeps campaigns on their toes and shores up flaws. Having Hillary anointed the victor before Iowa caucus was definitely a very risky play by the Democrats.