I've been on several sizeable projects where what you suggest, i.e., starting over, was tried. When they jumped into it without any clear idea of what they were doing, the attempt failed in each case.
The most expensive failure cost the firm then employing me, which shall remain nameless, $8 million. Early on, I told the project manager and my boss that the project was doomed and why, in considerable detail. Then I made sure everyone on my team found jobs elsewhere.
If you can't answer any of my questions, I'm going to avoid participating. I don't like failure.
Ed Poor