IMO, grab the T9 gears for all your alts, extra badges grab the hierlooms then quit the game until new expansion is out. At least you can choose whichever of your alt to level to 85 firsts.

I've played my lowbie alts in the random dungeon finder. It's way more fun compared to playing at 80 haha. Everyone so undergeared, and clueless on what to do. Some twinks with fully decked in heirlooms will end up being the tank. I had a rogue tank shadowfang while i healed.