*Shrug* I was just running GK as a last hurrah before diving more fully into Tau next week.
I think the power curve is pretty flat in 6th -- GK are good but not especially better than other armies ATM. I think you just have several veteran players with GK armies + the usual randomness led to that line up.
I can tell you with my list (mini deathstar of GKT in an LRC) my greatest fear was playing a Tau player with lots of Broadsides. Would have knocked me flat.