The only nastiness I found is that you can't join as 5 shammys. It says the group is not viable for lack of tank. The workaround I did was queued with 4 shammys and 1 of my druids, then kicked the druid, and put a shaman back. He won't get the badge or gold, but you can do another random heroic, and kick a different shaman for a tank, and replace. So in order for me to farm the frost emblems on the dailies, I have to run 2 heroics.