He wasn't ever going to be a RB1 like Love or Price
He has performed well but when you consider he was never more than RB2, those who thought he was more than that were bound to be disappointed.
This was his first year as a possible RB1. And although he is a valuable player because he does a lot of things well but other than being really good as a receiver and good on 3rd down, he isn't ever going to be the guy at RB.
James and Walton are more instinctual runners who move quickly through the hole.