I'm more than just an "idea guy." I have skills in programming and artwork. I don't think we have the same view on Kickstarter. Not all funded games on there will succeed, but that's whey they're on Kickstarter... to get funds they otherwise wouldn't have to have their games developed. I think I'll aim for the 50% mark before putting it on kickstarter. Kinda insulted you brought up scamming. Maybe some people put up projects hoping to get a free ride, but that's not me.
I'm saying KickStarter attracts alot of people, skilled and unskilled, and the only way I personally have to sort between the skilled people (who may have poor pitches) and the unskilled people (who may have very shiny pitches) is that the person either has a track record of completed games (even if small), or the person is far enough along to prove to me that they have skill.
I'm not at all saying you're inexperienced or just an "idea guy", I don't know you so I don't know if you're unskilled or experienced. You could be very skilled! I'm not saying you aren't.
I'm just sharing A) How you can convince to me that you are skilled (track record or nearly finished).
And B) How I view the responsibility of developers posting on Kickstarter.
Once funded, and the money released to the developers, the developers instantly benefit. The only way for the contributor to benefit is for the promised project to be released. This is why developers like Kickstarter. Zero risk for the developer, 100% risk is swallowed by the contributors. It's unbalanced, and most the contributors don't realize that (from ignorance*).
Thus the developers' responsibility is to maximize the chances of the contributors not being ripped off, since the developer already has been benefited. (You want people to fund you for two years. Even if you fail in the project, you already immensely benefited People paid your salary so you can do what you love, and be your own boss, for two years. So those two years (and the development leading up to it) need to be focused in making sure you don't fail, not for your benefit, but for the benefit of the contributors who paid you to succeed.
*Ignorance as in, a lack of knowledge and understanding of the effort and risks of game development, and a lack of discernment to measure who's legit and who's not, and a tendency to get carried away by their passion about what's cool and interesting.
It's like paying a contractor in advance for a project that he says he is able to complete, and then he says, "Oops, I underestimated the money/time/labor, and I either can't complete the project or you have give me more to actually get something finished. I already spent what you previously gave me, so I can't return it, and the project is half-completed, so it's worthless to you."
[Edit:] I'm answering two questions here:
1) How far you should be before Kickstarting, if you want to convince me to contribute. This is the question you asked, reworded.
2) How I, as a developer, approach my Kickstarter responsibilities. This is the question I for some reason thought you were also asking ('How do you approach Kickstarter'), but in re-reading your one-line post, isn't actually asked anywhere! Whoops.