Aldriana compiled a best-guess FAQ for 4.0.1 for rogues. Again, this is all mostly educated speculation, but it gives us a good reference at least for some common questions.
http://elitistjerks.com/f78/t105659-4_0_1_rogue_faq/Also, Hit gems are now blue, and there's a new Hit/Haste cut for green gems. That'll likely be a good one to fit into yellow sockets.
You can, and probably should, also reforge any crit on your gear over to hit/haste (depending on what you need as far as hit cap), from what I am reading.
Mutilate: speculation is to run Slow/Fast. Before it didn't matter to much but now it seems to be more of a difference. Swapping weapons back and forth between slow/fast and fast/slow while in combat is a bad idea now.