What makes you think he's a better defender than Dummett? Also, what makes you think anyone in the Scottish league could make it here?
Don’t get me wrong, Dummett has surpassed my expectations of him this season, and done a lot better than I thought he was capable of, and I’d be happy to keep him as a squad player. However, I think he’s probably reached the peak of his talents and is unlikely to progress further than what we’ve seen. From what I’ve seen (admittedly only on the telly in Tierney’s case), Tierney has far better pace and ability to link both defensive and attacking duties. He could press higher up the pitch than Dummett is capable of, and deal more effectively with pacey/skilful opposition players when they are attacking. He’d also be much more able to overlap whoever we had playing LW and has a better final ball (imo). However, like others have since said, unfortunately I can see him leaving Scotland for a far better (or more progressive/forward thinking and owned) team than us.