So far I've been using Dragon God on Kokoro (alongside Nitori for the +30% CLD), and it deals absurd amounts of damage. I'm sure Tokiko would do more, but I have WINNER on Tokiko, so...
... speaking of which, WINNER is a really amazing class. Sure, none of its spells, alone, are stronger than Dragon's Breath. However, they give you a surprising amount of versatility. Vorpal Blade is strong enough to be used as a standard single-target WND attack, Sword of Light pierces through almost any defenses, and Wand of Destruction wastes away anything not immune to all statuses. Between WINNER and Dragon God, Murakumo almost feels like a "second rate" subclass now^^ I mean, sure, it's still quite damn good, but the main problem is that, since it lacks composite attacks, you are generally stuck either with a weak Murakumo Slash or a weak Start of Heavenly Demise (sorta like the same issue with Suwako's moveset).
On another note, now that I defeated most of the bosses in the new patch, I'm starting to theorymon again for what team is the best for "infinite progression" - like WINNER farming in TL1, basically. Many of the same concepts still apply in TL2 as well, I think:
1) You generally want a tanky character on the left, a healer (possibly AoE) on the right, and two damage dealers in the center
2) You kinda need to be a bit bulky, and to be immune to as many statuses as possible - which is why I'm planning to equip most characters with 2 MGL + Medicine of Life and Tokugawa Statue. Sure, better items will eventually come around but it seems to me that this is the most balanced combo atm, especially for mixed attackers. Medicine of Life, in particular, provides you not only with insane bulk, but also near immunity to the most deadly status ailments (paralysis, silence, death and poison). Notably, it still leaves you uncovered against FIR/CLD/WND/NTR attacks, but I don't see how to patch it without giving up a huge amount of stats
However, I see also a major difference. In TL1, when it came to damage dealers, the main focus was on non-elemental nukers, and in general anything with really high multipliers, regardless of the element. Nitori, Youmu, Yuyuko, Shikieiki and the like were a must for any serious WINNER team (Suwako could work too, but she was a bit too frail IMO, and let's not even touch on Kaguya). Literally, once you had your tanks (2-3 between Keine, Ran, and Yukari), and your healers (Reimu and Minoriko), it was as simple as stacking as many of these nukers as possible, and throw them all at WINNER until either he died or you did.
In TL2, however, elements do matter. Unlike in TL1, where WINNER had no weaknesses, in TL2 weaknesses are a concern, and they shift throughout battles too. So, you generally want not only to have as many nukers as possible, but to have them spread throughout as many elements as possible. Given that running a tank + 2 DPS + healer set up is still advisable, though (I personally recommend Renko and Maribel, especially since Renko's status resistance ability allows you to "cap" your chars without overinvesting on items), you generally don't get to field entire "families" - though with Kinship boosts after awakening, that's less of an issue.
The problem, here, is that not all elements have it equally easy. Some elements, like PHY, SPI and DRK, have an abundance of nukers. Furthermore, any char can be turned into a SPI nuke thanks to Murakumo subclass. But some elements have much less choice available. With that in mind, I was thinking about compiling a list of plausible nukers for each element (not counting subclasses, ofc), trying to cover each element with at least two characters. I'll prolly come up with a more detailed list/analysis in the next days.
EDIT: Is it an oversight of the wiki, or does Koishi not get Proof of Kinship when awakened?