Did this change recently? It has never stacked in the past. It does stack with Imp LoH though.
You've always been able to have both Inspiration and Ancestral Fortitude buffs on you, but they never gave a total of +50% armor. It was still just 25% for both. I don't believe this behavior has changed at all.
That said, even if it doesn't stack with Inspiration, it's still one more opportunity to give the tank 25% more armor. And Chain Heal + Ancestral Fortitude is amazing, since you're giving armor to three people who've proved they were likely to get hit. You could do a lot worse for 3 talent points.
Gone are the days of fights where it's just one dude taking damage. And usually the people taking damage are going to be relatively clumped up, so chain heal shines.
On Gruul, use it on melee for cave-in and Shatter damage.
On Magtheridon, it's handy for shadow bolt volley damage, but not that useful after that.
On Hydross, use it at the start of each phase to bounce among all the add tanks and MT. Also on Water Tomb.
On Morogrim, top off people after Earthquake.
On Lurker, use on DPS after a Geyser/Whirl, or to top off people on a platform dealing with an Ambusher.
On Karathress, use on people taking Spitfire/Water Bolt damage.
On Leotheras, not that useful but still good for Whirlwinded melee.
On Vashj, good for topping melee off after someone got Static Charge near her, and for Forked Lightning healing.
On Al'ar, bounce it all over after Flame Buffets occur on transitions.
Void Reaver couldn't have been better made for Chain Heal.
On Solarian, use it after her AoE and on the Agent stack.
Chain Heal is the reason I switched back to a Shaman after playing a Paladin. I simply could not stand only having single target heals. Either Gurg's spec or 0/11/50 are outstanding specs at any level of gear.
I like Elemental Warding but I find it precludes having EVERYTHING I want in the Resto tree. I'm 0/5/56 right now, and while I also love Improved Ghost Wolf (and the points in Healing Focus, and to a lesser extent Tidal Mastery are negotiable) I also like Focused Mind. It's mostly a PvP talent but there are a number of trash mobs (and Gruul!) who have silences. There are also a number of Heroic mobs with interrupts, and my groups/tanks have been saved a number of times by Focused Mind coming up huge. Elemental Warding is more reliable, I just chalk it up to playstyle. As for Nature's Guardian, I thought it sucked (from the tooltip) until I did some testing, and now I really like it. It procs off DOT ticks, if you're DOTed at low health you're practically guaranteed a proc. It takes Purification, scales with gear...it's just a good talent, though at 5 points that deep in the tree I can see why some have reservations.
As for hybrid builds, I think 30/0/31 is an overrated travesty. You have to make so many compromises in both trees that you end up short-changing yourself at any role you pick. I raided as a 36/0/25 spec for a long time after BC came out, and depending on how you spend your time in-game it can work out really well. With a hybrid spec you REALLY have to make sure all your talent points are paying big dividends, and 30/0/31 just forces you to spend points where you don't want to (Improved Restorative Totems or whatever it's called) and skip things you DO really want (Storm Reach, Elemental Precision, can't have 5/5 of both Unrelenting Storm and Lightning Mastery unless you are insane and don't spec Elemental Fury). Ultimately, you're trading a TON of healing viability (Purification, Imp. Chain Heal, the list goes on) for some mediocre DPS and Unrelenting Storm. Maybe that's okay with you, but it just wasn't enough for me once we were into SSC.
Because shamans are needed in melee groups first and foremost.
If you have an enhancement shaman, great! If not, then welcome to OOMville. I used 18 Super Mana potions in one evening of raiding yesterday, for example. I'd love to give myself a shadow priest, but I can't justify it when it'd mean leaving a melee group totemless.
I'm running 11/0/50 ( http://www.wowhead.com/?talent=GE0zZZEcMtAeotcd ) although to be fair the points in elemental and the two points in nature's guidance are mostly because I currently have no alts on my shaman's realm (transferred a bit over a month ago) and they're of some use farming with elemental gear to me.
I'd have to agree with most people here that you simply cannot ever understate the usefulness of imp CH. I can't imagine raiding as a healer without it.
I honestly love to use chain heal and spam all day long. i advise other shamans in my guild that heal to take the "Chain Heal Challenge" and only cast that during the raid. I am currently 3/0/58.
One question though, what rank CH do you guys use? I find that anything lower then max rank heals too little when im chain healing during murloc AE and solarian(sp?) packs.
I "believe" I read a while ago that Rank 4 CH is the most effective heal we have, in terms of MPH. I might be wrong but I couldn't seem to dig up the thread anymore. My trash gear consists of normal gear + 3 peice t2 + Scarab, with using a combination of rank 4 and 5. Bosses I will pretty much stay on rank 4 chain heal with rank 10 Healing wave as an alternative.