What is changing for rogues in 6.1?
Not much, this is a pretty light patch for us after all the frenzied hotfixing of the previous couple months.

DfA got buffed, is it any good now?
Probably not. I can’t guarantee that DfA is never worth using but based on a lot of experimentation with Simulation Craft its hard to show DfA as a dps gain outside of some very contrived scenarios.  One thing that should be less of a worry in 6.1 are DfA whiffs.  At least on a stationary target the problems with DfA whiffing should mostly be fixed.

Should I change any gems or enchants?
Stat weights should remain the same however if you are using Mark of the Shattered Hand on your weapons you want to reconsider.  There was a bug with shattered hand in 6.0 that inflated the proc rate for classes with a source of non-haste attack speed (rogues with SnD), this bug has been fixed in 6.1.  Shattered Hand in 6.1 is now like the cheap enchants of previous expansions, if you aren’t concerned with topping meters and/or want to save a little money it’s a good choice but it is no longer the best weapon enchant choice in most gear sets.

Should I change my rotation?
Nope, there are no mechanic changes in 6.1 that require a rotation change.

What is BiS for BRF?
I don’t know and I don’t care.

Have other questions, ask on the forums.