I played hockey all through college as a forward and a couple times have thrown on goalie equipment just to try it out after practice. I have found that being a goalie is a completely different skill set than being a skater, it's almost like you are playing a different sport. It's all about playing angles, body positioning, quick reflexes, and spatial awareness - those skills are important for skaters but we usually focus on play formation, north/south speed, agility, and passing.