Throwdown: 4-shamans and a tank versus Mixed group

[Rin]

Numbers aside:

I am running a 1 pally - 3 elemental - 1 resto combination, and it works great for clearing instances (Heroics) - However, I'm looking at potentially swapping in a mage, druid and priest.

The main reason for that is that, until more 5 man content is available, it gives me something to do - And then it will eventually give me greater flexibility in building the team I want in the future + If I ever were to go back to raiding, I could have a bigger choice in classes for my main

From a pure class mix perspective, I do find the dedicated healer + chain heal combo a bit lacking for group heals - And I'm curious what a priest would bring here - Basically if I take group damage today, more than 1 character has to start healing for it to be a fast group heal, which drops my dps (granted, right now I'm healing with all 4 to "group heal" and I guess I could reduce that a bit to make it smarter).

If we're going to compare the Priest with the Resto Shaman, we need to look at a few things:

Holy spec'd Priests bring Circle of Healing (though, the 6 second cooldown has really killed this spell at the moment), Fortitude (+STA for your group), larger heals (G.Heal, etc, but with a cast time), Renew (HoT), and a healing prayer for your entire group.

Resto shaman bring the Totem farm (as described by Bigfish), Earth Shield, and Typhoon (6 sec. cooldown, single heal). The main forms of group healing come from the Healing Stream totem and the Chain Heal spell.

Is it worth losing the totem farm and Earth Shield for the healing abilities of a priest? I would argue that it's not, as you're going to receive much less utility in your current group composition from the Priest rather than from the Shaman. Circle of Healing + Prayer of Healing combo will only gross you so much health (CoH gives you around 756 health, Prayer of Healing gives you 2209 base health. You're going to be losing about 936 health (base/talents)/minute just with the loss of the healing stream totem. On bosses, this will mean that you're going to be healing more with the Priest simply because you've lost that extra 936 health/all group members.

More on this later.

Cheers.