How do you possibly know that when he's barely had a kick in the 1st team?
Ralston has made 4 appearances at celtic to Jenny's 2 at Everton, ralston has also made 10 appearances for qos, kenny made 17 at oxford and 7 for Wigan. (Yes I looked them up didn't know off the top of my head) so that argument doesn't really stack up.
I have however seen kenny play live for both the first team and the u23 and been impressed by him. It's my opinion that he is more than capable as a back up to Coleman. I have no opinions regarding ralston, for or against, I don't know enough about him.