Originally Posted by
Pristi
Discipline has, in terms of healing power only three things going for it. Shields, Grace and Focused Power. So +6% healing from Grace, Strong shields and +4% spellpower from FP. If you look at the holy tree you see that Spiritual Healing alone (+10% to your healing spells) is way more usefull in terms of healing throughput. Now the rest of the talents in the Holy tree also boost healing/efficiency a LOT. Spiritual Guidance, Empowered Healing together with talents like Test of Faith and Serendipity for mana. Lightwell is now worth casting, so a second usefull heal, CoH is still good assuming the bugs get fixed.
What discipline brings is Spirit Buff, Grace and Penance. Grace however is just to make up for the poor healing throughput (Since no healing spells actually get buffed in the disc tree), and no where near the holy tree buffs. Penance is a nice and effective heal, but on a 10-8 second cooldown. Spirit buff has definetely lost it's shine (Improved Divine Spirit isn't even worth taking anymore, in a raiding environment).
So if you'd ask me, who would I pick if I base it purely on the ability to keep a tank up? Well Holy seems a lot stronger at doing this, coupled with the ability to AoE Heal effectively and in the off-chance that the tank does drop to low and gets pummeled you have Guardian Spirit together with a talent that increases your healing and chance to crit to bring the tank back up too full. Disc, I don't see a discipline being an "effective" Main Tank healer, apart from the "I put my shield up to buy the others more time to heal the tank".
On top of that a discipline priest is STILL the only healer that actually has a negative effect on the tank he is healing, unless a death knight. Whether or not the effect is big or not, it's still negative and imo destroys the synergy between tank and healer. Because let's face it... if you can pick why go for the healer that heals in a way that has a negative impact on your rage generation/mana regen, if all the other healers are just as good in keeping you up? I'd say a druid as it stands now is twice the healer a discipline priest will ever be (Very strong HoTs, combined with a stronger and more efficient fast heal and a stronger and more efficient bigger heal and an ability to make your next cast instant = huge lifesaver).