The general gist of it seems to be that although Dyer is clearly better with a ball at his feet than Nolan will ever be, he was injured far too often, and Niola, despite his limitations has scored 11 goals from midfield this season. And for those reasons some people would rather have Nolan in this squad than a young Dyer. I personaly wouldn't, but I can see where there coming from.
Nolan isn't shite, and Dyer wasn't Lionel Messi.