I think they are hugely important factors. Information is power and they have a huge amount of influence because of the trust people have placed in them.
Like it or not, wikileaks will influence all of our lives. To say that they are a mere conduit and have no obligation to vet or squelch the information they've been given is to also assume that they will never get their hands on information (factual, or otherwise) which may have a direct, negative impact to you personally.
Useful information is rarely neutral. There are nearly always winners and losers when it is disclosed.
They have been accused of releasing PII before, but they claim to be a journalistic organization. My take is, they're more concerned with delivering data dumps than sorting through terabytes to redact innocent details, because they're more of a dump site than a news site. And as such, it's raw information to consumers. I expect it to be pretty fully digested if I'm going to call it a news or analysis product.
The way I look at it, WikiLeaks is basically a parallel construction. We have no idea how or where the info came from, but if it's a map to the bodies, we go there and see if it's accurate info.