Paladins also have pretty good absorbs now. Illuminated healing their mastery leaves an absorb behind after every heal. They also have pretty powerful single target healing and great aoe healing without having to use chakras. The reason why disc has traditionally slightly lower HPS is because absorbs have less overheal. The key however is slightly not 10-15%.
I understand how pallies heal. They are great at aoe healing in stacked encounters not in general. My understanding has been that disc having lower hps is because of their absorption capabilities. Regardless, pallies have nowhere near the absorption capabilities that a disc priest has.
In fact the buff to illuminated healing is a big headache for us, because it makes it tough to get aegis absorbed in a low damage phase. Remember that the smallest absorb gets eaten up first.
I can see how that might be a headache, but (and I'm truly not trying to be snarky here) welcome to what all the other healers have been dealing with since the bubble-spamming disc priest came into being. Remember that shields get first bite of the damage apple while everyone else gets whatever's left over meanwhile a fair chunk of their heals get pushed to OH. This too is kind of a headache.
In general disc operates at a low efficiency. Especially with multiple paladins in the raid.
Mainly folded up with my above comments but, pallies creating an environment where disc operates at low efficiency is part of the 'why disc needs a buff' argument?
Who says we are mathing out healing. The purpose of the math is to explain how our healing spells behave, not to mathematically model every fight. Its not impossible to do it, its just pointless. Everything you need to know can be inferred from simpler models that don't require so much effort.
My point is that theorycrafting healing has a long and storied history of inaccuracy. I'll wait and see how things shake out at 90.
Anyway, as someone above me already stated, this thread probably isn't going to end up anywhere near useful in ...3 ...2 ...