Candidates need to be vetted in the primaries. That is the purpose of primaries. Trump is not being vetted, just like Obama. The voters need to know what “scandals” or shortcomings are going to be raised in the general election before they vote on a nominee.
I agree with you about vetting candidates. Debates are hardly the sum of vetting. We aren’t going to learn more from 92 debates vs 15 debates.