As an SK, I went with the 2-hander, though at the time it was a very tough choice. One thing to remember about using the 1-hander while main tanking, there's a pretty good number of slash immune raid mobs in the game. There are some I use a slasher for (Borxx, Overlord, Drayek, etc.), however, it seems there are more slash immune mobs than crush immune (at least before they turned Darathar into a [Removed for Content]).