Patch 3.1 is going to be a BIG help to all the Mutilate Rogues out there. FINALLY they will have some Glyphs that will be "must haves" for them (providing of course we get to keep them, at least one has already been removed since yesterday.) For a long time that has been an issue that has plagued that spec. Frankly some of these glyphs I was surprised were not released at the beginning.
Patch 3.1 will bring Rogues a total of Seven new glyphs that I know of (since one yummy has been removed).
With duel specing being offered with this patch some rogues are also looking at the possibility of doing a "trash spec". Basically specs that focus on giving a lot of AoE. When looking at this they MIGHT want to look at things like Glyph of Fan of Knives and Glyph of Killing Spree. Of the two I think FoK is the more viable, (though your weapon usage is still going to be key with this move.) As fun as Killing Spree is for AoE FARMING, in a raid situation it really wouldn't be that worth it in my opinion. I know personally I like to pair it with Blade Flurry since they both share 2 min cool downs.
I really wish Blizz had given us something more in the way of Minor Glyphs or even something for the supposed "Meta" glyph slot that there were rumors of when the glyph system was first introduced. That empty circle in the middle just bothers me.