I used to have the EXACT same setup as you do. 1 pally, 1 priest, 2xmages and 1 shaman - all level 70 with about the same spell damage. I thought that it would be the ideal pve group. I was wrong.

I found it just to hard to play - you have to think to yourself, all the time, what should the tank do, what should my healer do, what should be mage do, what should my shaman do - it was just too complex for me and not very fun to play at level 70.

I rerolled 4 more shaman and made my pally tank my raiding character. So now I have 5 shamans (for 5-mans) and 1 prot pally for raids. I'm a LOT happier now. I can do more instances with the shamans than I could do with my other group by a long shot. I killed the 2nd boss in SV so quick that it bugged out the instance and didn't let me open the little thing to get the boss doors open the other day. It's so much easier to play it's nuts.

On the other hand, you might not want to give up too quick - once you get more spell damage on your pally you'll be able to hold tons of aggro on everything and it might get a lot easier.