I currently have a 5 shaman set up with RAF. My problem is coming soon where I have to decide the set up Im going to use. Im planning on being pure PvE--Instance running.

So the question is for anyone who has run 70 pve groups nis :

Should I keep 5 shamans
Should I swap in a pally at 59 and RAF it to 59 and continue with 4 shaman and 1 pally.
Should I swap in a 70 warrior, geared for heroics (one of my single box chars)

Now Ive only played a pally to 45 so am clueless to their tanking mechanics. Ive played the warrior exclusively pve as an instance tank so know it pretty well. Know it well enough to think I may need all my concentration for multi mob pulls so a pally may be best?

The 5 shammy set up seems ok as Ive seen vids of 5 shammys completing Mgt Terrace heroic.However Im a bit stuck so any advice be great.