If you really feel the need to tolerate the Kopite and answer his question, tell him that Naismith is crap, Barkley is being misused, and it says more about Martinez.
Barkley may in fact being misused on occasions as you state, however it doesn't fully equate for how poor his performances have been.
How many good performances has he had this season? In fact, how many reasonable performances has he actually had? There aren't many.
Equally, Naismith has not always been played in his most suited position at times, and is quite clearly limited in terms of ability compared to Ross.
Yet, it would be hard to argue with the fact that he's imposed himself more than Ross and has contributed more in terms of goals and assists.
Steven is a not a better football in many aspects, but this season he has been a much more important component than Ross through guile alone.
Many are now more concerned when they see Ross in the starting line up rather than Naismith; that surely can't be a good sign for Ross.