At the end of the day, the coach is only as good as his players. But the difference between a great head coach and an average one is one who can put average players in a position to be good. An example, Jim Harbaugh. Essentially the same roster as last year, the team's 5-1. Rob Ryan has shown he can't elevate average talent into the good tier with his schemes and motivation.
No. I need to see him "produce" on a consistent basis before I consider him HC material. Right now, the only thing that makes him a HC candidate is happenstance - he's related to Rex Ryan. He hasn't produced top ranking defenses. He hasn't produced All Pro players. He hasn't produced anything besides a reputation for blitzing a lot (or too much, according to people in both Oakland and Cleveland) and a surname.