Depends on your definitions of missed and good.
He is AFL quality and one of the better defenders that the saints have. Is he better than MJ? No and I doubt he ever will be. But we have had to draft extra people so that we can find someone to fill a spot in the backline that he was penciled and partly groomed to fill. After all in teh draft you don't bet that everyone will make it. I would think that you have to take 2 or 3 players for every spot you want to fill. So replacing Roberton, given we go nothing in the trade, has meant that we have taken Brady Grey, Tom Vandeleur, Michael Wood in the draft and we redrafted Crytown (not saying they are better or worse) and we could have been using those picks to find a forward.
Roberton has cost us plenty. I miss him because of the missed opportunity cost and because he may not be flash but he will play 100-150 games for the saints easy. No matter what others say, nothing says successful AFL player better than 74 games in your first 5 years of senior footy. Fyfe is a star and has only managed 105 in the same time.