I wouldn't recommend going 72, to be honest.
Not because it is frowned upon because it actually is, but the reason being that sooner or later, according to feedback from GM's, you'll be able to only join at level 70 again for arena's and then you'd be forced to go to level 80 if you feel like doing more arena's. I can't speak to the battleground but to my fair thoughts, same thing is going to happen.
If I were you I'd stay 70.
Classwise, there are several BiS shamans that I know. Unfortunately, their armoury is currently filled with resto and/or PvP gear. I can give you a link to some shaman that I know, nontheless.
Keep an eye on their armour, if it's not correct according to specs, it'd be very close nevertheless. Ironclïff is PvE, whilst Drazo is focused more on PvP.
Ironclïff and
Drazo
Do have a nice day further on
yours truly
Shinela
^.^