a few questions about the AA tree...

i've been pondering over my AA points for a week now and i'm just banging my head against the wall about my final choices. i haven't been able to find much in the way of help in game, so i'm hoping someone here might be able to offer some good advice! ok here's my questions...
1. Herbal Expertise - the AA choice on the shaman tree > stamina line that removes the power cost of basic cures and makes them cast faster. is it worth spending AA for? i'm thinking it's not, and i'm leaning towards Immunities under the intelligence line. what's the opinion of Immunities?

2. i had a hard time deciding if i should dump AA into the skill that increases the return on Soul Cannibalize, or if i should skip that and pick up Cannibalize, or if i should have both. what's the opinion on that?

3. what do you think of the skill Ancestral Avenger? do you find yourself using that skill? it seemed like a good idea to spend AA points on increasing this in the Defiler tree, but i also have Soul Ward. they are both kind of an "oh crap" skill and after thinking about it.... i can't decide which would be more useful or if i should have both. what's the opinion on this?
4. what AA choices do you think are a MUST HAVE?

Minsipone@Antonia Bayle wrote:

Finally, you did not specify what kind of spec you were shooting for. Are you at level 90 and raiding? Are you lower level and soloing? Do you stick primary to grouping? There is a lot of missing information that would help lead you in the right direction as far as what people have found to be the most useful AA setups.

thank you for responding! did not think i was going to get any input. i am level 86 and working towards 90. i dislike raiding and doubt i'll ever get into that. my main focus is healing for groups.