So.. I'm 35 at the moment, fully heirloomed. Disc is just crazy, it's so beyond OP. With a Shield that absorbs 2k damage, and a 60% speed increase every 15 seconds.. When does this OPness end? I love the spec, but it's just too OP. :/
All low level bgs with full heirlooms on any class is OP, it's not just disc. You probably won't start noticing the stat decreases with leveling until you hit end of wrath early cata. It's been a bit since I've bg leveled, so I can't really remember when it happened, but it will.