Different positions mate. Ibbo and MJ are 1 and 2 in his role, he would be 3rd string. If he was that important to us we would have tried to sew him up in 2011 surely? Rather than leave it until his last year under contract and be left with the prospect of him walking like he did.
He was offered a contract extension in 2010 on top the standard two year contract every draftee gets. Why would he be offered another extension midway through his first extended contract?
Who knows where he may have ended up? As
Tayl0r has said, he could well have ended up as a defensive mid or tagger. And given how the backline has struggled with injuries to Ibbotson, McPharlin, Johnson and Silvagni over the past few years, he may have played more games than many think.
I don't rate Roberton, but the club clearly did. And the club continues to rate a number of other players I don't, and continue to play them in the senior side, instead of Peel where they belong. So your to assertion that Roberton would be with Peel: I don't agree.
I reckon if he was still on the list he'd be getting regular games, people would be complaining that Alex Pearce is better and should get a game, and you'd be telling everyone that the club is in premiership mode, can't afford to gamble with young players and to back Roberton in.