I only watch the episodes which includes Goran Visnjic. The relation between Abby and Luka was adorable. They were the best couple in the series.
He is a very talented actor. I first saw him as bus driver in Welcome to Sarajevo which was a wonderful first class film then the bad guy in practical magic with Nicole and Sandra. Then ER. I know lots of people who start watching the show after Goran was introduced as Luka.
I think that he definately deserves to be a bigger star. Once I heard that he would be in the Bond movie but unfortunately this information was wrong. I wish to see him as a leading actor in a big Hollywood movie. A villian in Bond can be counted too.