Crux is BIS dagger, despite what the Kara dagger proponents claim. The BIS off hand dagger though is still the Brutal one.
I have every rogue weapon that could remotely be considered BIS, situational PVE, PVP etc. I mean... all of them well, besides Nifflenewbs because I'm 70. Best dagger combo is Crux/Brutal. BIS overall is still the glaives.
I'll just wait here for the Blade of the Requitted crowd to come and go NYAH NYAH NYAH UR WRONG AND LET ME TELL YOU WHY followed by formulas no one cares about them except them in support of their misguided religion of supporting inferior weapons just because it has more gem slots.
Okay, just so I'm not flaming overtly? There are tons of choices for rogues at 70 that leaves people dead in 3 seconds. There is no universal BIS for weapons just what you consider BIS for how you play. I say this because I've seen rogues top boards with glaives, dual fist weapons, Crux/BOTU, Nifflenewbs and probably combos I can't think of as I type this.
This class has more weapon BIS possibilities than any other at 70. Hell, we can't even agree if Mongoose, Berserking or 26 agi is BIS enchant.