Trilarion: This major difference is exaggerated. The success of traditional pre-orders can decide about the amount of content present and many of the KS projects are already in a advanced state, kind of existing.
Some projects are in an advanced state, but the discussion about whether people have enough information to back a project is typically about projects which aren't in a state where such information is available. Projects like DFA, Wasteland 2, and frankly most big game projects, existed, if at all, in a very early state (such as a design document, a prototype, or nothing in the case of DFA). Small indie games are typically in a more advanced state because they need that to be convincing. Which suggests that people are indeed not going in blindly (they are willing to give experienced developers more of a leeway, while requiring more proof from less experience ones).
Regarding people being disappointed with a project's failure, that's natural, but it doesn't mean much. Investors are disappointed when a project they invested in failed, patrons are disappointed if the creator fails to accomplish anything with their money. However in terms of mindset investors tend to accept up front that they are gambling with their money and people who pre-order never accept that.
I think Zolgar said it well: "Kickstarter is a Crowd-Funding platform and a gamble, to call it anything else is inaccurate". There are similarities in mind set to investment, to pre-ordering, and to patronage, but there are also differences between Kickstarter and any of these.
