Testing Xuen on a target dummy gives me 704k damage from lightning, 243k from melee (this was with an int pot on accident, so dont let it taint your perceptions, my average has consistently been 800k-850k~). I'm not spending another 10k for a gem or the 1500 valor on my heroic staff. My spellpower gain from a raid is something like 3-4k, nothing significant enough to tilt it that much. (and a second use has him at 800k damage.) For funsies I threw on my 2H 509 from lei shi (no enchant/gem/upgrades, obv) and it only did 800k. Granted, the 517 has more sp and int so obviously 2h's work better, but the lack of stats makes it worse in my case. Anywho, that averages Xuen to .96 million/use assuming single target, which is most fights. We'll be generous and assume raid buffs boost it by 50% (lol, not happening). So, we'll assume it somehow manages 1.5million/use in my gear. That puts it...at 3mil on Garalon. the amount of healing I get from chi torpedo in 2~ minutes. At less healing than I can get from using all 3 chi torpedo's at the same time (and spread over a longer time interval.) See, chi torpedo can be weaved inbetween instant casts for near-zero interruption on actual healing, making it (essentially) free and added burst healing. Meaning I can get very strong use of it during burst damage that happens on fights.
Also, your sweeping statements are so incorrect it's laughable. "Garalon is the single most ideal fight in the entire game for Chi Torpedo. Yes, it is very good on fights with huge raid-wide damage constant throughout the fight, bravo." Really? You do realize that Xuen requires people to be taking damage consistently for 45s for it to be worth it as a raid CD? What, you're using it to heal tanks? Healing Sphere will do it better. There's very few fights where Xuen is better than Chi Torpedo, it's raw throughput and the fact that it can be weaved inbetween our instants for increased burst is very, very strong. If you're going to say you want Xuen for spot healing, then maybe you have an argument....but using a CD that has 1/6 uptime for spot healing is very unreliable so...dunno what else to say here, it's not able to fill that role, basically.
Tsulong is better than garalon, btw. As well, Xuen does overheal, by the way. You haven't been in my raid, so don't attempt to tell me what my raid healing looks like. If you think that my raid goes 45 seconds without being topped a single time or eminence smart healing (which is delayed actually heavily delayed, if you didnt know) healing a target at full health, then you underestimate disc priests. I used to be like you, I thought Xuen was where it's at. But it's really not. Xuen averages 1.2mil for me single target. Chi torpedo averages significantly more than that.
PS: When I made my Xuen cleave 3 targets it was hitting 2.2mil~. Meaning 2.6~mil healing. Too bad it doesnt do that on most fights huh. Before you make statements about how good something is on raid bosses, you should actually have it hit a single target to test its damage, because theres no way you're averaging 1.6mil single target with Xuen, when I'm stacking int/crit and not even breaking 1mil single target (from multiple uses).
PSS: Xuen has never cleaved legs for me. He always stands behind the boss, like he does on every other boss, which just happens to be no where near any other legs.
---------- Post added 2012-12-20 at 01:39 AM ----------
Taking note of raw throughput is important so you can relate it to other fights in terms of other blanket heals expected overheal (which is normally around 50%). Even in that case chi torpedo beats Xuen.