To understand why Riley was hired, you have to understand why Pelini was fired. Pelini had a mammoth temper, he rubbed fans/media (and likely his boss) the wrong way, he showed little progression year-to-year, had no prior head coaching experience, his teams routinely suffered massive blowouts over the latter half of his tenure and you could sincerely argue his teams had plateaued.
Now, that's the umbrella picture. Enter Mike Riley, who has a ton of previous head-coaching experience, his personality is polar opposite of Pelini and had a reputation for developing talent.
The reality is Riley was an image hire with a lot of potential, and most notably, his experience as a head coach was supposed to help the team avoid some of the big let downs that haunted Pelini. So far, that experience has not translated to the field consistently.
I'm nowhere near the realm of giving up on Riley but I think I'm a lot more patient than most fans. I don't think all coaches or situations are created equal and it very well could take a season or two for this staff and team to reach their potential.