Apparently my post got ate.
For pure DPS it is greatsword spaming Resolution or Torcleaver. For multi-step light SC's it's using Ragnarok, for multi-step dark SC's it's using Scyth. Other then Liberator Scyth really falls behind GS, and Liberator only wins because there isn't a Mythic GS for AM3 silliness.
Light : Resolution -> Torcleaver -> Scourge -> Resolution -> Torcleaver
Dark : CR -> Insurgency -> Entropy -> CR -> Quietus
Side note, with the HP bonus from Drain II/III now lasting 3 min you can do some really cool stuff. MB a DSNV Drain III off a dark SC and your looking at 4~5000+ HP. Turn on souleater and have a WHM cure bomb you.
For which WS is strongest,
GS: Resolution no question. The mechanics of fTP transfer and multi-attack procs have it beating Torc every time. That being said, Torc can make light with itself and depending those Light SC's might be worth more then loss in damage.
Scyth: This is difficult because they are all situational.
Quote:
Entropy: 1.075 = 4.3 85% INT
Quietus: 3.0 = 3.0 60% STR / MND, -15% defense (17% attack boost)
Cross Reaper: 3.5 60% STR / MND, scales up
Insurgency: 4.18 20% STR / INT, scales up
Entropy has the highest fTP, and because it copies multi-attack procs are worth a
little more (1.075 vs 1.0). The mode sucks on it, INT is a horrible mod for a physical WS. You don't get Attack, Accuracy or fSTR out of it and all the heavy armor you would want to wear has high STR / VIT and not INT.
Insurgency is a mixed bag, it had potential but SE never raised it's mods so it doesn't scale well. Liberators work out only because they have a +30% WS damage on it.
Cross Reaper is actually pretty decent, especially since it scales really well with TP overflow. Having a 60% STR mod really helps scaling on it's damage, the 60% MND is meh but it gives it approximately the same total WSC as a 80~85% STR WS would have due to iLevel stat vomit.
Quietus, this WS had so much potential. The mods are the same as CR, so pretty solid there. The fTP is kinda low at 3.0 and the TP mod is essentially an attack bonus. SE should of raised it's ignore defense from 10/30/50 to 25/50/75 or raised it's fTP to 4.5+. Currently with TP moonshade your looking at 15% defense ignore which is the same as a 17.6% attack boost. Not strong enough to really make a difference on stuff where you'd want that. Quietus does make darkness though, so it's useful as a closer or to SC with others.
To compare with Cata since some of you are glued to your Apoc.
Catastrophe: 2.75 fTP, 40% STR / INT, absorbs HP.
With Apoc your looking at +40% damage which can be modeled as an fTP boost for 3.85 pseudo-fTP. Has darkness property like Quietus so can be used to double on a darkness SC.
All in all Scyth WS's have good SC properties but really bad damage. As the highest DMG weapons you would think that SE would focus on STR and big damage, but they seem hell bent on keeping them for CosPlay purposes.