I don't know if we are discussing the same player, but when I saw Kjaer playing last season, he was nothing more than a decent defender with some good potential. He was also error prone, but this can be reasonable considering his age. He's also a bit slow as well.
Better than Chiellini? Come on man you can't be serious. Chiellini, Lucio, Samuel, Pique, Puyol, Vidic, Ferdinand, Terry are just the first names that came to mind who were better than Kjaer this season.