I don't think Tammy's point was misunderstood, it's just that Billy handles the show just fine. He doesn't appear overwhelmed by the proceedings, so why would he need a co-host on set?
Mind you, I think Todd is a very underrated host, but I don't think he necessarily needs to be on set, either. Just like I don't think Drew Carey needs a co-host on TPiR. Would I like to see Todd do something other than host a "quickie" game? Sure. But I don't think him hosting a few more mini-games is the answer.