Some napkin maths:
According to Rawr in Arcane BiS gear:
3/3 SotM: 90.2 DPS
1 +damage: 1.9 DPS

So 3/3 SotM equals an average of 47.5 SP. Since Incanter's Absorption lasts 10 seconds you'll need an average of 47.5/0.15=320 damage absorbed every 10 seconds, that's 1920 damage every minute.

So when do you absorb more than 1920 damage every minute on average? In nearly every fight if you have a Disc Priest and a Val'Anyr Druid I'd say, in many fights you'll absorb way more than that.

Not only is the additional DPS you gain from the gained mana quite low (DPS/DPM-wise going from a ABSpamXMBAM to ABSpam only is horribly inefficient) but Molten Armor in general has been better since the change to being spirit-based, especially when glyphed and having 2T9 (Mage Armor glyph and 2T9 with Mage Armor are next to useless because regeneration doesn't go over 100%).

Going by Rawr in BiS Arcane gear you get ~150 DPS from Mage Armor and ~800 DPS from Molten Armor.

I have been looking through this thread to find out just how much haste is going to push me over this limit during heroism, but haven't come accross a definte figure. Can someone help me? I also have the Scale of Fates.

Edit: grammar

If not required to save it for movement, I like to use POM on the 4th AB cast if Mbarr hasn't procced yet. The GCD incurred is just enough time to see the Mbarr buff come up should the 4th (instant) AB proc it.

The vast majority of fights right now involve some sort of frost or fire damage making the improved wards trigger IA as well as being excellent mana returns for only a couple of points on the way to IV in the frost tree.

Is it really a dps gain to use a gcd for a fire/frost ward, and then use the extra mana for additional AB spam? Or do you use the wards to help with survial, and the extra mana you get is just a bonus?

It's not really a DPS gain per se as it's still only a 30% chance to gain mana back. Should you prioritise it over DPS? Of course not. I personally use it to soak some damage on intense healing fights (taking MA for the same reason) and any mana return is simply a nice bonus. If you time it within phase transitions and forced movement situations, then the DPS loss from that GCD is minimised. As with all situational talents and filler points you take it if you think it will benefit you.

Read through the last couple of pages for a more in depth discussion on the topic, but the general conclusion (and correct me if I go off on this matter) is that "yes, it can be useful - albeit marginally."

As near as I can tell there are essentially two uses for PoM.

#1 - Use PoM early and as soon as it's available to cast again. Essentially, a PoM arc blast saves roughly 1-2 seconds from your rotation. If used as much as possible, in a 5 minute fight - you've saved 5-6 seconds from an absolutely optimal rotation (i.e. no interrupts to the rotation and no running). This isn't a big difference obviously (nor is it entirely likely); however, it may become a bigger difference in longer fights.

#2 - Save PoM for times when you are running. Essentially, you would save PoM until such time as you would need to run away from something (such as standing fire) or you are running to something (such as Icehowl after charge). This method has the added benefit of increasing (or at least sustaining) your dps while on the move. However, you risk not using your PoM as often as you could because you may not encounter something which requires you to move in every encounter (or at least not as often as you would need to in order to use PoM as often as you possibly can).

My personal preference is strategy one for the very reason stated at the very end of strategy two. The benefit of using PoM as often as possible gets exaggerated because of the Arcane Potency proc. Additionally, with the first strategy (because it is optimal to use PoM on the 4th arc blast) you can control when you use PoM. In the end though, the difference between the two strategies may be so minimal as to suggest a third strategy which is, essentially, "It depends on the encounter." If you'll move a lot, save the PoM for movement time. If not, use as often as possible.

A PoM - AB macro is nice if you have to move, it's certainly much more dps than arcane barrage. If I don't have to move, personally I use it as my fourth AB in the rotation if I don't have missile barrage - the crit bonus will mean more on the fourth application, and the global cooldown means you have time to react to a missile barrage proc.

I am quite certain that using it in that way is a much smaller dps boost than using it when you have to move though

EDIT: The previous reply was much more in-depth, it wasn't there when I started typing this

Well iv just been trying with a Disc Priest to keep a shield on me as much as posible, this is definatly the most effective way of using IA, in a Razorscale test i gained around 500-1000 Spell power not sure how much but that was definaly a good increase for 10 seconds. In a fight such as Anub were there is lots of raid damage and everyone is taking damage the use of these shields is so valuable to the raid and will also increase DPS.

The use of our Wards imo will not be effective to break a rotation to pop a ward on the chance that im going to take damage.

I can't seem to find the 3.2.2 scaling values. I did a search, and I've looked through the last 20 pages of posts. Would you please repost them? Thanks