Oh right, rankings for the even remotely plausible ranks.
Yosuke - High Middle. I'm still convinced he's pretty solid. I'm still not convinced he can swing any higher, though. I guess that the Auto-Endure does tip him into High Middle territory, at worst.
Chie - Heavy. Turn-two mass overkill and neat equip options off decent speed. Then, we have Miori Shirt insanity. Doesn't get as much out of Auto-Endure as her peers, but considering how difficult spoiling her delayed overkill can be, this is often hardly an issue.
Yukiko - High Middle. The frailty... honestly doesn't matter as much with the solid damage, elemental spoiling and equipment possibilities, and she's well off against other Middle healers. Auto-Endure also sees plenty of use with the damage. Ice-weak, but it's not the worst weakness you could have. Unlike...
Teddie - Middle. Lightning weakness sucks ass. Otherwise, Yukiko with slightly more physical durability, less resource depth and notably worse equip options and elemental spoilage. The weakness pushes him back enough to lose the "high" spot to me.
Kanji - High Middle? Sorta like Chie, but sorta not. Trades a notable amount of speed, cannonballing power and the Auto-Sukukaja option for somewhat more consistent damage and a lot of durability. Losing trade, but both are fairly effective at their game.
Naoto - Middle/Heavy. Okay, so she's a pure ID whore. But she's a pure ID whore who's decently speedy, and I consider her ID turn one due to respecting its hit rate from in-game mucking a bit more. Add to that the Auto-Endure and she... just tends to get the turns to ID people, and she has the awesome of female equip options -and- a nice elemental spoiling set. She is obviously pretty lost against those who mock the ID unless they suck at slugfesting/durability, but... the set of spoiling+I win status gets a whole damned lot of PCs. And hey look what happened with Nina2 and Jean, who reamed Middle seasons off ID alone. Naoto's ID may not be anywhere near as accurate (70-75% < 85%-95%), but she has more tools to get the turns she needs than those two. So yeah.
Kunino-Sagiri - Heavy. The durability is certainly pretty excellent (think I peg him at 2.5x PC HP). Being stuck with 4HKO DAMAGE AW YEAH at full HP and always losing the first turn just fails, though, and while his spoiling game is neat, he doesn't even come close to a OHKO to average durability at his best, and it always needs those wind-up turns (to put it up at first and when Quad Converge runs out). Then he reaches 25% HP and he's stuck with 3HKO damage forever and ever. He's just utterly lost against Heavy-level healers, and Godlike slugfesters make him weep beyond all reason. Full elemental walling can also get him, although it's rare. Handling the likes of Emily and Alena is also problematic for him, since Quad Converge only gets elemental magic: he's just as vulnerable to physicals as anyone else, modest evasion aside.
Evil Kenji - Middle. Turn two ID and Heat Riser are neat! However, he always goes last. Oh, and he's running off like 0.7x PC HP. But wait, he also uniformly 4HKOs as a backup! Winning combination there. The physical resistance gives him some staying power against Middle physicallers, at least, and he has those elemental immunities to help him out. Gives him spoiling power, I guess, but he's pretty hilariously inept when he has to face ID immunity or 3HKOer mages in general. Fun little bugger in his incompetence, at least.
Ameno-Sagiri - Godlike. My respect for him went down a fair bit due to realizing the middling durability+losing initiative combo is baaaaaaaaaaaaaaaaad. 1.5x~-ish PC HP doesn't give you a ton of leeway when you always start injured. The double-acting+notable offense of both types+P4 debuffs+Bewildering Fog setup mass is brutal, though. Even has a cruel PC-killing move at very low HP, but, as I said before, I'd be impressed if a PC managed to get through the offense, debuffs and limit phases and got yanked by a 25% HP range PC-killing move. >_>
Izanami - High Godlike. I allow the two phases and those three free turns (the formchain, plot weirdness aside, seems pretty legal, since there's no out-of-battlescene transition and even buffs/debuffs remain). So, we get someone who starts with... 3/4s of Evil Kenji's HP (that's honestly veering into Chidori durability territory by -that- point), no doubleacting and her best offense is low 2HKO Lightning damage. However, you OHKO her and now she gets three turns for free to smack you while she gets ready to change into her big bad (but still sorta frail. Ameno-Sagiri HP and you're about five levels higher. Not a negligible difference) form. So, the opponent has to enter Ameno-Sagiri's raw slugfesting/debuffing power, more accessible status and better physical offense with a 1.5x PC HP disadvantage in the damage race that ensues. Oh and she halves physicals and immunes Lightning, because she totally needed spoiling powars. This package is some seriously scary shit. She feels honestly beatable enough (really high-end PCs could possibly blow through that package with the relatively free time she gives them for buffing, for an instance, and durability gods can withstand the assault long enough to peg her down, especially with the relatively poor durability on the second form), but damned if she isn't frightening. Of course, you disallow the first form and now she's Ameno-Sagiri with -less HP- and no Bewildering Fog. That's still a Godlike, but so much worse it's not even funny. <_<