Caucus supporters believe that neighborhood elected representatives (delegates) do a better job at vetting candidates than all registered party voters. Registered party voters are thought to be too complacent and, therefore, cannot be trusted to take the time or make the effort to honestly investigate and compare candidates. In reality, most delegates do not vet all candidates with an open mind, but are often elected in caucus based on the candidate(s) they are already supporting. An open primary would solve this problem and ensure that everyone who votes has a voice in the election process.
Any person who intends to vote can meet the candidates, read campaign literature, attend meetings and compare candidates. Electing someone to do this for me does not improve the democratic process but weakens it. If I vote for a delegate in caucus, I have, in fact, given my vote away to someone who may or may not see the candidates the way I see them. No, thanks!
I will investigate the candidates and cast my vote for myself at the ballot box. Newbies and incumbents are accountable to all the people, not just to the few delegates who go to convention.