how is this for RBGs?
I have used this CR myself extensively and would say that if you are a knowledgeable enough player to configure your settings in an optimal manner, assign hotkeys, and position yourself properly - it is very strong. The multi-dotting and rot damage really shine with this CR. I myself use a trick where I enable AoE for Affliction, but set the unit count to an arbitrarily high value so that it is not casting seed of destruction - rather applying DoT's to each enemy individually. It is very rare that I will not be top damage in almost every single battleground and sometimes 2x-3x other dps.
Using it described above I cannot quite find something to improve in any major way and would rate it 10/10.
If you do not configure settings and just walk around with the CR turned on, it's still pretty good - but you are missing out on a lot of the customization and potential of this CR.