We had 4-6 tanks for Gruul, so I offered to go ret. HKM went pretty well, though in retrospect I should have taken Hammer of the Naaru. Gruul was terrible for me. Someone pulled by accident while I was relogging, so I missed about 20%. I logged in stuck in stone, eventually bubbled out of it. Later I died to shatter, got battle rezed, and died to the next next shatter. I don't know if WoW even realized that I did any damage because it was so low.
Since we were done early we decided to go kill Mag. I've never killed him before.
I think he was overnerfed. The fight was a joke. We had tons of time to kill channelers, infernals were rare, and I don't think blast wave even kills people anymore. We had a mistake on the first run that caused dead clicker issues. The second run was very smooth.
I got one of the holy paladins to judge wisdom on the second run. Before that I'd been chaining PvP mana pots and still going OOM. With JoW I think I used one, maybe two. At the end I was 4th for damage, though there were disputes over the accuracy of the meters.
I got lucky later on and got into a MgT group on the third boss. It took a few wipes, but we downed her. The warrior and rogue had the trinket, I think the hunter passed, so I got a Shard of Contempt. The proc is great and combined with my new neck (I forgot to mention buying Brooch of Deftness) I'm now at -4% dodge/parry. I still need more hit since I'm at 4% before precision. I think switching my violet eye ring should do the trick. I'll get surefooted too.
So all in all it was a pretty good night for smashing. Since my guild apparently has too many tanks, I might stay ret.
 I forgot to mention that on the third obss of MgT our priest died so I pulled out a healing mace and shield and kept the remaining warrior and hunter alive. That made me fell all paladin inside.