As the saying goes: "Ideas are worthless. It's the execution that counts."
Crowdsourcing feedback is a great idea and I highly recommend that, but I believe the most important thing you should do is build a small team of people that all believe the product is worthwhile pursuing. That will improve the product idea immediately and will allow you to build faster. Also, it will make the crowdsourcing of ideas easier because people can tell you're serious about chasing the dream and having more people to respond to inquiries will increase the level of communication in the threads.
Next, seek expert advice and really understand if what you're building is actually feasible. If yes, can you get these people as advisors on board? Get your hands dirty and really figure out the technical challenges and start putting your own time and capital behind it. I, personally, would feel very uncomfortable investing in something that the founder hasn't staked a significant amount of his own time and money into. This aligns the incentives for everyone and removes a portion of the risk for a potential investor.
ICOs are a real way of democratizing the funding process on a global basis, but just having a white paper and no (at least alpha) product is a tough sell and will only get harder from here on out as investors in ICOs are becoming more educated. It should be an alternative to VC and not a free-for-all where people raise money without having shown that they can execute and deserve the investors' trust (and money!).
Hope that's helpful!
