Krahn is a very good goalie. Basically any hype and enthusiasm surrounding him was shot when he suffered some knee injuries (limiting him to 16 games in one subpar season), and eventually was cut from the Calgary Hitmen. He was a lost cause then he had a very successful (albeit short) stint with Seattle and led them to a terrific playoff run and now is clearly showing signs of being the goalie that management saw in him.
He's a big goalie and I would say is more positional than reflex. For the past several years, he has been seing loads of goalie coaches teaching him motion techniques that take pressure off his knees, which is why the problems are almost non-existent right now.
He's got talent. His draft year did have one of the most stacked junior teams of recent memory, but a 33-6-0 record with a .912 pct. is still pretty impressive.