Well now that the talents are out, we can start light theorycrafting a cata shadow rotation. My guess is that with Mind Melt, Mind Spike will be a 50/50 filler spell with MF. I could see this rotation working out:
DP, VT, MS, MS, MS, SW:P, SF, then just use flay when there are already 3 stacks of Mind Melt and keep MB and DoTs up.
Thoughts?