Having spent time on an aircraft carrier, I can appreciate the importance of “lights” 
A buddy of mine works for the company producing the radiators (or is it intercoolers) for the F-22.
And it makes sense that they can’t fly until they get the safety issues like ejection dialed in. I knew that they did some revamping after most demos, but I had no idea they practically scrap it and build a new plane from the ground up. I guess they can integrate the technology from the demo better if they re-design.