Dunne has the mobility Joe doesn't. He is also a better player with ball to feet. His range of passing etc is good. That is why he is in the team. If you look at Gallagher Gogic, Fraser and Dunne they all are comfortable with the ball to feet and are more creative.
I like big Joe but I prefer our current set up. The clean sheets we are having don't lie.
If we move on Joe and get a better forward player then its all good.