Originally Posted by
[-Spiritus-]
You mean the guys that got stuck w/ IMP-DS duty? Yeah, those weren't Disc priests. The Disc priest wasn't born as an independent and singularly viable spec until 3.0.2, and really wasn't balanced until 3.0.9. Saying you were a disc priest in BC is like saying you were feral DPS; you were there because of a buff.
I also know for a fact that there are tons of Disc priests that aren't tank healing. This is mostly due to the fact that paladins still can't sustainably raid heal and 95% of Disc priests from WotLK were bubblebots who are trying to find a replacement for the cheese [hint: its not tank healing].
Just because this is a fact doesn't make it optimal. It is mathematically impossible for a Disc priest of equal skill and item budget to outheal a Holy priest while raid healing. Since you can be Holy in 5sec, the only reason to stick in Disc, from a minmax perspective, and raid heal is if you have one paladin for each tank in a given encounter and having PW:B & PS makes the fight reliably easier.
Also, ES on the tank means squat for 10% phy reduction uptime, especially with most shamans' crit levels. It requires an actual tank healer to keep up a near 100% Insp or AH uptime, anything short of that is not worth the 2TPs.
Disc priest talents and "signature" spells all point towards single target healing. Our single target healing is getting buffed in 4.0.6 like crazy and our raid healing is getting significantly nerfed. Our 4pc fits in perfectly with someone who is tank healing.
Disc desires to be a tank healer. Can it raid heal? Sure. Can it "float aimlessly around the healthbar grid not on assignment?" Sure. However, what Disc does best is effective and efficient single target healing.