I think this year we are going to find out that we have a much better group of wide receivers than we previously thought. I've always felt that WR is the one position where Kubiak was most reluctant to trust young players.
I honestly think he showed lack of trust to the point that it was detrimental to their confidence and development. I still say that's why Walter hung on so long. Kubiak trusted his decisions above anyone else's talent.
I think O'Brien will be the exact opposite. He seems like a guy that will challenge the young guys and reward them with playing time if they respond.
My prediction is that at the end of preseason, there will be a few WRs cut that we all hate to see cut, and they will end up on active rosters for other teams.