This is the fatal flaw in the program. The whole reason startup culture exists is that we don't have a way of knowing in advance what ideas are really worth pursuing, short of giving them a try. But this program would create a board of experts whose job it would be to try to predict which ideas had a reasonable chance at success.
The obvious outcome would be a huge distortion in the kinds of startups foreign nationals would found. The value of a green card is far higher than the expected value of a startup, so the process would turn into a bad example of grantsmanship - trying to tailor your proposal to what you think the committee wants to see, and then making sure your startup stays solvent long enough for the permanent residency to come through.
Rather than taking real risks and trying to innovate, the role startups are supposed to take in our economy, we would be encouraging an extremely conservative startup culture, whose real purpose would be to secure green card status for the founders lucky enough to get in the program. How likely are you to bet the company if the consequence of failure is getting kicked out of the country?