(1) Crusader Strike. Using CS is a small gain, with a caveat. Now, of course you'd want to maintain Holy Shock on cooldown, so the question then becomes is it worth using CS over Holy Lights or Divine Light on Beacon? A good way to determine this is to discover just how much healing 1 Holy Power gives you. In most cases, this would translate into 1/3rd of an Eternal Flame. Leaving out the boring math, 1 HP, especially taking Divine Purpose into account, heals for MORE than the raw healing of Divine Light. So we have 9,000 mana for 1 HP, or 21,600 for Divine Light base healing + 1 HP. Thus, Crusader Strike is more mana efficient than DL (this does assume that you are specced into both Eternal Flame and Divine Purpose, otherwise it is suboptimal). There's also the added benefit that CS often returns mana via Insight, so it costs 6,600 instead of 9k. But the big caveat to this is that you have normal miss chance, along with a boss's dodge (and parry, if you hit 'em from the front). This means that CS is unfortunately not HP on demand and has the potential to waste mana if RNG disfavors you. So, I do NOT advise using it in general circumstances, only for bleeding edge content, or in PvP usage.
(2) Light of Dawn glyph is an HPS loss. Consider. You can heal six targets for 100%, for 600% total healing, or four targets for 125% each, which is 500% total healing. This glyph is only advised for when doing 5-man dungeons or for PvP. I could suggest it for certain 10-man raid comps, for when you have 3 or 4 ranged spread out that need regular healing, perhaps on Wind Lord, but since you have to sacrifice a Major Glyph spot for it...
(3) Is DP more effective with the T-14 than Holy Avenger? Unusual question. There are two things to consider, and then one answer. Firstly, Divine Purpose becomes stronger the more Holy Power you gain. T-14 4-piece gives you more Holy Power. Thus, it benefits DP, and to a pretty decent degree (perhaps 30% or so). HA is harder to determine, because its value depends upon time sequences and your individual haste AND whether or not you have Bloodlust/Divine Favor up. To get the most out of HA, you would do Flash of Light/Holy Shock, HP Finisher, repeat. But using Flash of LIght is mana inefficient, Holy Shock has a 4 or 6 second cooldown, and you'd normally be using AoE spells rather than single target.
With the 4 piece, assuming 25% haste.
Holy Radiance (2 second), LoD (1.2), HS (1.2), LoD (1.2).....
Holy Radiance (2 second), LoD (1.2), HS (1.2), LoD (1.2).....
Holy Radiance (2 second), LoD (1.2)... which is 14.4 seconds, giving us just enough time for another HS and then LoD (1.2). So in this scenario, HA gained us 12 Holy Power.
Without the 4 piece, assuming 25% haste.
Holy Radiance, LoD, HS, LoD....
Holy Radiance, LoD, wait .4 seconds and then HS, LoD....
HR, LoD... but now we're at 14.8 seconds, so we can't get in the last HS, since there's still .4 seconds to go. So we only gain 10 Holy Power.
Now, if we started with HS instead of Holy Radiance, both scenarios would net us the 10 HP. However! HS has a chance of procing Infusion of Light, which would reduce the cast time of HR by 1.5 seconds, which means that WITH the 4 piece, you could maintain your rotation. Without the set bonus, you'd start having to decide to wait 1 second or use another HR, and so forth. It gets ugly. And haste changes things SO much.
But since you wanted a comparison, it looks like the 4-piece only improves HA by 1 Holy Power per minute guaranteed, with an additional plus 1 each time you proc Infusion of Light during HA, and you'd have 3 chances. On the other hand, the Four piece is said to generate about +4 Holy Power per minute on average, and Divine Purpose basically multiplies your HP gains by 1.33, which means the four piece gives DP +1.33 Holy Power per minute.
So I guess the 4-piece generally improves HA moreso than DP.
But the note I wanted to mention... you don't select HA because it's more Holy Power or less HP. You grab it because you need the cooldown instead of generalized mana efficiency.
(4) Threshold for Eternal Flame versus Light of Dawn. There are three answers, depending upon whom you cast EF on. Assuming that all of the Mastery shields get used and there's no overheal, and that Light of Dawn hits 6 non-beacon targets...
Looking at just my tooltips, which is fine since bonus healing, Mastery, and Crit affect them all the same:
EF: 73,500 initial + 12 ticks of 8100 = 175,500
LoD: 22,800*6 targets = 136,800, plus Beacon transfer of 20520
Light of Dawn heals 157,320 total
Tank (Beacon target): Just the base 175,500 healing, so the numbers are fairly close.
Fellow Raider: Stronger, because of beacon transfer. 263,250 healing, a good 67% increase over LoD.
Self: Double HoT from Eternal Flame makes it super powerful. 416,250 healing, more than TWO AND A HALF TIMES the healing of Light of Dawn.
Now, what can really make or break the difference is overheal and mastery, which we can't forget. EF, because it's single target and a HoT, has a lot of Overheal. However, the rolling effect on it means that the mastery portion of it AND any other heals you slam on that target, has a good chance of being used. Honestly, this changes on a per fight basis so that I just consider it a wash.
In other words, it is ALWAYS better to use EF instead of LoD when you can help it, but it means paying attention to tank health, and possibly swapping around your beacon before laying out an EF. And knowing how your co-heals react to damage.
(5) Hand of Purity DoT reduction work with Brewmaster? Wow. I hope not. <checks up on it> Um. It worked on Stagger during 5.0. I do not know if it still does. I will do some more research to be sure, though it'd be nice if anyone else knew the answer. I mean, that would turn HoPurity into, what, a 30%+ DR cooldown for 6 seconds every 30, so long as the monk is staggering?
(6) Battle Healer for Holy spec? Almost no benefit. I do about 500 melee dps, or 2,500 with Crusader strike. You'd likely only manage 1 minute worth of damage on a real fight, with amazing macros so you're always attacking while you cast instant spells. So... maybe 9k healing (45k with CS)? And at the cost of a major glyph. Even with Crusader Strike, not worth it.
(7) Specific tricks for bosses I'll leave up to others. The only general advice I can give is to use all the friggin cooldowns, paladins have tons. Especially bubble. Find a way to incorporate Hand of Sacrifice and Bubble together to ignore powerful mechanics AND get some free mitigation in.
Edited by Wards on 4/7/2013 7:42 AM PDT