As Usual Suspects moves into Hammerknell, I've been very impressed by the complexity and difficulty of the instance so far. It's also very cool looking. There is a lot for rogues to do in this instance, but so far, one thing is clear: Sabdancer is king.
Murdantix is going to be the new benchmark for raid DPS in Raid Tier 2, just as Plutonus was in Raid Tier 1. It's a single target fight with good uptime on the boss and not too many secondary mechanics to worry about. It looks like 2.2k DPS is the highest benchmark being floated about.
Matron Zamira is a fun and challenging encounter that basically requires Saboteurs for AOE and has a few mixed mechanics as well. We were able to get Shard First on this encounter and if you see "skull" talk on the forums, you know what its about. I don't anticipate the fight will be much more difficult next week.
We haven't done any of the other bosses, but judging from videos and discussions, there is a wide array of mechanics and strategies that should keep us busy for a long time. However, if you're a rogue DPS, it really looks like Sabdancer is the only spec you need.
Oh, and a little humor.