While this is a great idea, I am not sure if this will really be practical. Let me try to put it in context by giving an example.

So you have a new team that develops a good idea into a project and does ICO. The assess the coin/token price to be 10 cents and ICO is a success. The coin/token is added to multiple exchanges and start selling in the range of 8 - 12 cents.

Right then Jan 2018 happens and entire Crypto market tanks for a long time (like now) and then the coin is now worth $0.001 cents (I am not making it up, if you look up there are at least 50+ example of this).

Now at what point one need to decide to release fund to investor. Remember the team is still committed and believes in their project. Also there is chance that what they do in their road map 2 year (or more) down the line can make this coin/token worth $1 or more.

Also when a project tanks (and dev and other team disappears) who are you going to reach out to get money back?

My 2 coins ..