I think Alan could have done a job for us but, unfortunately, like one or two others he felt he should be playing regular first team and was not happy being just a squad player. This is something that happens at all clubs. Lads become more ambitious than their club can allow so they make a song and dance and are then allowed to leave. Sometimes they're successful where they go. Sometimes they fail. One of the points that should be remembered before critisising such players is that they all want to earn more, just like the rest of us, and if they cant break into the first team they are not eligible for the bonus's etc.
I wish Alan, and any other player, every success in their choices to progress in their career's elsewhere.