The collaborative play call can work, but you have to have one person who is definitely in charge. The outside input can be good and help prevent the play caller from becoming blinded by their tunnel vision. One person has to be steering the ship, though. If it is play call be committee, that is not going to work.
When OB said it was a collabortive effort, I don't think he meant play to play every play. The collabortive part comes into play when game planning. They agree to which call should be made for specific down & distance as well as score and clock situations. It's not easy being a NFL HC regardless of what many on this board thinkI always envisioned this really only working if it went something like this.
Play caller: "I'm calling X play, you guys have 10 seconds to tell me something you saw that makes that a bad idea. If not then I'm calling it in."