I think people are very justified to be a bit nervous about this situation. With this hire you have a defensive minded first time head coach, and a young position coach moving up to be OC. These guys are certainly rising stars, but this is clearly a high risk situation. No one knows how it will work out. I am an optimist by nature, but to not acknowledge the risk would be dishonest, and naive.
Ash was likely ready to take the next step. Moving directly to HC at a Big Ten school is a significant jump, so there is still significant risk involved. He may or may not be capable of being an HC. Plenty of hot P5 coordinators flame out at the AAC/MAC level. Ash is being thrown into the fire of the best coached division in college football. While his promotion is probably appropriate, it is absolutely higher risk.
Many, myself included, were hoping to back fill his inexperience with a former HC at OC. Someone with some experience running a team to help Ash grow into his role. Instead, we have doubled down, hiring a position coach from an AAC team to be our OC. That is extremely high risk, and by any measure he is skipping a few rungs on the career ladder.