I don't think this illumination change is the end all be all - it will just completely and drastically change our style of healing to FOL spam and HL for very, very few situations as it is too much mana to cast with any reliability or redundancy in any raiding situation with an expected return of 400 mana every 5-9 casts.
What this does do is force us to look at itemization alot differently, MP5 will be alot more tantalizing now, and hopefully Blizzard realizes this and looks at nearly all of the Raid gear currently in game focused towards Holy Paladins. Almost every single piece has a large amount of crit, and nearly none of it has any MP5. I'll be dumping various T4/T5 pieces for blues, as the blues are better in all situations for sheer longevity (which is all that matters to a Paladin as our burst healing is simply not cost effective now even with chugging pots.)
For those of you who think "Well now you have to chug pots like everyone else" - I used a Resto Flask and Chug Fel Manas + Philosopher's Stone buff with more gusto than anyone else I know. I exclusively live or die based on my Fel Mana Timers for some fights - specifically if I have to solo heal a tank, since the only spell I can cast to keep a tank alive currently is Holy Light max rank. I specifically would rotate DI Holy Lights until I got a crit, then use a DF Holy Shock for a return of ~400 mana just to squeeze out every point I could out of my mana and I'd still be running low at some points. (This is with 26%+ depending on fight Holy Crit, 1300+heal and over 60mp5). Its going to be an ugly readjustment period for all of us, and we're all going to have to regear to mail since that has much more attractive MP5 than plate does currently.
This will affect raids for a long time coming - specifically ours since we only have 2 Holy Priests, 2 Resto Shamans and 1 Tree druid in the entire guild - the rest of all healing is covered by 5 Holy Paladins. Granted we don't have everyone on every raid and generally end up with 6-8 healers for any given fight (5 for Void Reaver). Our longevity hasn't changed much as FoL is still ridiculously cheap, but this does completely crush any HP/S longevity we had, and I fear we're going to have to stack healers to compensate for this change unless itemization vastly improves, or Blizzard wakes up and realizes Paladins need more options now since our FTW button has been effectively cut in half.
Lets examine straight healing (assuming optimal raid heal spec - save the "utility" strawman arguements for another thread)
Priest : Most options. PW:S,Renew, POH, POM, Lightwell, Gheal, Flash, COH. Adaptable for any role and all situations - MT Healing, Multiple Target Raid healing, the only real viable party healing. Excels at them all.
Druid : Lifebloom, Rejuv, Swiftmend, Regrowth, HT, Tranq. Excels for passive healing on multiple targets, can single heal a target decently and fares well in nearly all situations albeit not optimal for single target healing unless out of treeform? (correct me if I am wrong, our only Tree Druid doesn't discuss his leetness.)
Shaman : Chain Heal, Earth Shield, Healing Wave, LHW, Healing Stream. Best multiple target raid healer in my opinion with Chain Heal, and spamming Earth Shield on the MT seems to be quite the mainstay in my guild - and Healing Way lets downranks of Healing Wave reach fairly recockulous levels of HP/M. Again versatile but not as much as a Priest - Chain Heal is the real winner with self sufficient logic for choosing the best possible target.
Paladin : Holy Light, Flash of Light, Holy Shock, BoP. Best (pre 2.1) single target healer for mana efficiency and HP/S. Post 2.1 still maintains the best mana efficiency but loses huge amounts of HP/S so solo healing viability drops considerably. Holy Shock has poor use considering limited range, small amount healed, poor coefficient.
Suggestion: Maybe move Holy Shock and give Paladins a new heal somewhere in Holy? Something similar to PoMending or a "buffed" form of BoSac where we take a portion of the targets damage? (after mitigation of course). It just seems to me that the allure of Paladin healing is now gone, and I'm going to be a viable albeit decent solo target healer, but a one trick pony with FOL spam and alot of MP5.
Another possible option is to double the amount of healing Holy Shock does, and increase its cooldown to 20 seconds? (leaving the damage the same)
As a side note, I was excited for a moment when I read Imp Holy Shield, since I thought that means they would be making Holy Shield a trainable talent, and Imp Holy Shield would be like Imp Shield Block for Warriors. It wouldn't do much for most things, but at least for some fights I could gear swap and OT if needed, or maybe grab an add for a few seconds and spam block.. but I guess I'll have to stick with my retinue of taunt and kite for now

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P.S I just realized I vendored the KZ Plate healing gloves with MP5 and 2 blue slots

. Looks like its time to petition for my T4/T5 replacement!
Unintended buff : BoSac now has a raid role - put it on as many people as possible assuming you are the 4th or 5th Paladin, and group with a Shadowpriest for pre-nerf mana return levels

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