Lately I have been doing some various raid groups, ranging from PVP to PVE. I am also since wow 2.x been playing healing druid with healing range addon (x-perl). And I find the use of some group abilities more or less worthless due to different restrictions and cost in mana and CD time.

I define group abilities as spells/ abilities that effects your party, but not your raid. Spells I can think of from the top of my head is Traquility http://www.wowhead.com/?spell=26983 and prayer of healing http://www.wowhead.com/?spell=25308 I am sure that there are other spells just like them, please enlighten me. I do however want to diffrentiate them from Auras.

My main concern is that these are powerful spells, tranqility can heal around 30 000 hp. But in raid environments they are limited by the fact that the reciever must be in the same party, this seem like a non factor to a novice (been one my self). But take for example last time I was in AV and fighting Drek. Drek hits like a truck and deals out major damage all around the place, especially when aggro is not considered. To save the situation I see a druid poping his tranquility; I do a quick check on my raid status just to see the druid is using the 10min CD only to heal a mage not taking any damage. Since there are only 5 spots per raid group I guess blizzard whats you to be thoughtful where you place your members, which I can agree with, auras should have the need to chose for the right occasion. My solution would be to change some abilities to have a wider raid wide reciever group but balanced in the way that the more recievers the less healing per capita. Like the changes to mages AoE's.

The question is what balancing factors is there to consider and how would this effect the game as a whole?

Raid-wide heals have been suggested many times since MC days.

The main problem I can see is that they are potentially so powerful in raid encounters that balancing them in pure numbers terms would mean that the healing per unit may be too small for anyone to have an incentive to use such a skill.
There is also the issue of aggro too - the impact of any healer pushing out 1000hp (which, by todays terms is a decidedly small heal) to every member of a 25man raid in a single heal for example would be tricky to balance. If you allow for a talent to reduce this aggro, you could then be in the position of that becoming a "must-have" for that spec and/or class.

I would welcome the possibility of a heal that heals the target and everyone in that target's group though, would be a very useful skill and much easier to balance.

Encounters like Huhuran are a fair example of how having such effects be raid-wide but with a lower overall effect could be bad. While a lot of guilds went for specifically assigning healers on targets, some guilds (like my own) went for Prayer of Healing instead. That was only viable because you could set your groups up so that four Priests were healing the 15 NR sponges. Having the effect be raid-wide would mean you'd need to have more AoE healing going on to achieve the same throughput per player.

I think overall encouraging the planning to take into account 'Ok, this encounter has a lot of AoE damage on the melee, it's more beneficial to have a Priest in there in this case even it's a slight reduction in DPS' is superior...

Balancing would also ensure that either the throughput or the sustainability of such AoE heals would get quite low. And if the first is low, it just turns into a case of 'Why cast this heal in the first place?', while the latter would make AoE heals even more situational than they are. For example, Prayer of Healing, the spell I'm most familiar with as AoE heal having played a Priest for a long time, was an efficient choice when three or more targets in your group needed healing, in that case it justified the cost it has. A raid wide one would probably be balanced to be an efficient choice at a larger amount of people.

Circle of Healing

Yes it's a great idea, now if only Blizzard could make it actually worthwhile to cast.

A raid (or even just friendly targets) heal targetable like explosives or mass dispel would be interesting. The number of people the heal affects would have to be capped of course.

Well, I don't really count that due to its mechanics, which are clunky in addition to the lack of effectiveness. Why not just be able to target one person in a group and know that all in that group will be healed? I expect that Shaman may be slightly miffed at the potential devaluing of chain heal though

While CoH could have uses (if they make it worthwhile), the way raids tend to stack groups into utility class (melee grp, tank grp, ranged dps etc) negates much of the reason you would use it in the first place.

The main issue with CoH (and Lightwell for that matter) is that for a highly situational skill it's just not powerful enough compared with other highly situational skills in other classes.

I don't see a problem with raid wide effects as long as they scale appropriately (e.g. not with the # of people, but with the priest's gear).

In the 31/41 talent topic, someone suggested a meteor-like holy priest talent.. that doesn't have raid-size scaling issues. For example, it'd be a 30K heal spread across everyone in the area of effect.

Or perhaps a heal that couldn't be exploited to hit the tank for 30k?

I was going to say that as well, but consider what would probably be expected in terms of large mana cost and casting time.

And how often do you need a heal that large or over that many raid members where you can spare a very long cast time to do so?