I read another post of a boxer who was going 5x Resto Druids.
And then using Magma totems for AoE, as they just healed each other.
This I believe was for Arena against cleave type teams.
I think you mean 5 resto shamans (resto druids don't get totems) ... think you will have major troubles in arena going all healers. AOE is too strong to heal through from my experience. I respecced all my priests disc for arena and bg's and tried a few arena games and 10/15man BG's ... got utterly wiped. My gear isn't great, but there is simply not enough burst or sustained damage to be effective in arenas or BG's with 5 priests (unless your only healing AV). Disc priests can't mind flay unless you spec for it, but i think you're giving up pain suppression if you do.

My shamans tend to do better in BGs (not arena) as elemental, but still have troubles with more than 1 cleave. AOE shaman heal can't out-heal 2+ enemy AOE fire ...

My priests were actually pretty good as shadow - 5x mind sear can wipe their entire raid at belinda (even when i cast from outside the room) if they don't catch you in time, but are generally very squishy and run OOM all the time (having to shift out of shadow to heal) - very fun though.

I've almost got my last 2 druids (at lvl 55) caught up to my other 3 druids at 60, and plan to go resto on all of them for AV initially ... totally agree on the survivability of a resto druid - although I would like to hear from others on how well 5x druids do in BG's (not just AV).