As a young man, Dantes is naive, innocent, and full of forgiveness. When we see his transformation into the Count, a man appears..... full of vengeance, all grown up and bitter. He walks through life with his eyes wide open.
His persona of Abbé Busoni helps him to gain the trust of those he wishes to punish (and some of the people he loves), but the mask of priesthood also allows him to manipulate those around him. Lord Wilmore is the man I think Dante would have become had he never gone to prison..... all goodness and generosity.... thus, the reason the Count didn't like him. Must have been hard for him to allow the mask to slip..... hard to see what he could have been.