AA slow Sha's Reprisal
- pro: independant recast timer from spell slow.
- con: range and duration focuses do not apply. Also, it's rank 2, while most raiders will have rank 3 of the spell version.
For grouping/soloing both range and duration matter, so I've been using the AA version as backup if the spell bounces or to slow a second mob. For raiding, I'll consider just using the AA slow, as duration is not important on an early slow when a shammy is going to overwrite it.
Pet block has always been a special situations spell for me. I don't see the hp limits affecting group play at all.
Re: Dots. Unless you know something special about the mob resists, the cold dot just become one of your better dots any time your playstyle calls for using multiple dots. We've had the ability to stack poison dots for a long time (along with every other class that gets poison dots), so nothing really changed here. In raids, we usually don't stack DoT's because the debuff space is more needed by other classes, especially necros.
I'm playing with the cripple proc now. The stun proc isn't going to work on mobs over 100, so I think the general answer to your question will be based on the content you're killing, but it's something we need to get a feel for.