No matter which Democratic candidate you like or loathe the most, I think most reasonable people can agree that CNN was really, really awful.
As ever, it's really striking to observe the difference between the audience-generated questions and the journalist-generated questions. Wolf Blitzer's main interest is in asking questions designed to put Democrats on the wrong side of public opinion, even if those questions are about things like driver's licenses or "merit pay" for teachers that aren't really under federal purview. Efforts to reframe those questions by putting those topics in the larger context of immigration policy more generally or education more generally are derided as cowardly dodges. The point, after all, is to force a choice -- piss off an interest group, or say something that could be used in a GOP attack ad.
The real people, by contrast, ask about problems in their lives. The mother of an individual ready reserve member wants to know about Iran policy. The mother of an active duty soldier wants to know about military pay versus pay for military contractors. An Arab-American wants to know about racial profiling. Then the candidates explain what they think about these issues.
The voters are curious and want to learn where the candidates stand. Blitzer doesn't care about informing the public about the issues -- he actually objects when candidates try to explain their views on broad immigration policy issues -- he's just interested in trying to embarrass the candidates.
Oliver Willis added that in the post-debate wrap-up, CNN reported that candidates' surrogates told the network that their candidate did really well -- "REALLY? You went into the SPIN room and PAID OPERATIVES of a campaign think that THEIR OWN candidate did well?"