Originally Posted by
Atonement
While disc does do damage while healing, it's still a 'pure' healer. It doesn't trade healing for damage, instead you should consider it's damage as part of its utility (compared to say druids who have more cc).
Disc does very well with the right talents, let me use some numbers to explain.
Compare all the healer's "quick heal" spells, those are the 1.5 second, higher mana spells. We will assume no secondary stats, and only baseline mastery, and no artifact traits or legendaries
Disc: Shadow Mend: 750% spellpower
Holy: Flash Heal + EoL (10% baseline): 475% spellpower + 47.5% = 522.5%
Hpal: Flash of Light + Lightbringer (12% baseline): 450% spellpower * 1.12 = 504% spellpower
Druid: Regrowth + Harmony (4.8*3): ((350% *(40% increased crit chance)) + 60% hot over 12 sec (10% per 2 sec, 6 sec)) = 629.2% spellpower
Sham: Healing Surge + Deep Healing (24%): 475% spellpower *1.24 = 589% spellpower
MW: Effuse+Gusts of Mist (80% sp): 250% spellpower + 80% = 330% spellpower
As you can see, disc has by far the strongest single target, spammable heal out of all the healers, even without it's mastery affecting it.
All these other healer's masteries will increase their flash heal, but disc's doesn't, however its a simple matter of gearing for haste, crit and vers, and avoiding mastery to keep us easily on par with, or ahead of other healer's outputs for 5mans. On top of that, we take the grace talent, which basically gives us 30% more healing on shadow mend and PWS, and then we take Twist of Fate, which gives us 20% increase damage AND healing for 10 seconds after healing someone below 35% health. This makes our 5man triage healing extremely powerful.
On AoE, we will compare baseline AoE healing spells on a per second basis, 1 cast. Same assumptions, 5 targets max.
Disc: Penance + Absolution (Atone on 5 people) = (570%*0.4495*5)/2sec = 640.5% spellpower per sec
Holy: Prayer of Healing + Echo of Light: (200%*5)/2sec + 100%/6sec = 516.66% spellpower per sec
Hpal: Light of Dawn + Lightbringer: (180%*1.12*5)/1.5sec = 672% spellpower per sec
Druid: Wild Growth + Harmony: (238%*1.144*5)/7sec = 192.48% spellpower per sec [note, this isn't quite accurate, since the per second amount starts high and slows down]
Sham: Chain Heal + Deep Healing: ((400*1.24)*(0.7^0 + 0.7^1 + 0.7^2 + 0.7^3))/2.5sec = 502.54% spellpower per sec
MW: Essence Front: (110%*3*5)/3sec + (36%*3*5)/6sec = 640% spellpower per sec
Cooldowns
Disc:
Power Word: Barrier: AoE 25% reduced dmg for 10sec, 3min cd
Pain Suppression: 40% reduced dmg for 8sec, 4min cd
Shadowfiend: ~240%sp (hard to get an exact coefficnent on shadowfiend melee coefficent, extrapolating from logs) dps for 12sec, converts to 107.88% sp/sec atonement healing (total=~240%*0.4495*5*12 = 6472.8% sp, this is actually equal to about 2/3rds of a divine hymn or tanquility, its a bit weaker, but a bit longer, and also does dps and is mobile), 3min cd
Rapture: PWS spam, 8sec, 2min cd
Holy:
Divine Hymn: 750% healing over 8 sec and increases healing on targets by 10% for 8sec, double in 5mans = 750*1.1*1.1*2*5 =9075% sp
Holy Word: Serenity: 2000%*1.1 = 2200% sp heal, 1min cd, reduced by other abilities
Holy Word: Sanctify: 600%*1.1*5 = 3300% sp AoE heal, 1min cd, reduced by other abilities
Guardian Spirit: 10sec, 40% increased healing on target, prevents target death but is consumed, 4min cd.
Hpal:
Aura Mastery: 6sec, various effects, 3min cd
Avenging Wrath: 20sec, 35% increased healing, 20% increased crit, 2min cd
Lay on Hands: Max Health heal, 10min cd
Blessing of Protection: Physical Dmg immunity, 10sec, 5min cd
Blessing of Sacrifice: Transfers 30% dmg to paladin for 12 sec, 2.5min cd.
So as you can see, in terms of it's healing abilities and cooldowns, disc is just as good as any other healer.