Actual thoughts on where I'd rank people. Definites first:
Yukari - High Light of some sort. Her HP is pretty weak (80%), and her END doesn't help much. She lacks an amp (which she'd kill for), so her damage isn't that great. Lots of healing, at least, but that doesn't help her much when someone has electric damage. So yeah...decent Light, but not a Middle.
Junpei - Middle, likely. Probably need to run more tests on High Counter, but it's probably close to 33% overall. That + Regen and a rare weakness with a good null is great. Damage is below average unless using his HP-eating techs, but his HP and END are good enough to keep him going for a while with the anti-physical game he has. Thanks God his magical defense isn't based on MAG.
Akihiko - Middle, possibly on the high end. The ice weakness is balls, but nulling electric helps. His damage is good, ever so close to a 2-shot to most. His healing is great, and he has the stat-drops to help put foes into a wringer. His physical is also a decent back-up if needed, and his durability is pretty close to average. A good tough Middle, but that weakness does knock him down a good bit.
Mitsuru - Middle, probably the same as Aki. Fire weakness instead of ice, nulls ice instead. Damage is 2-shottable to most, and she has Mind Charge and a decentish status to fall back on. Also has the healing, though her physical is nowhere near as good as Akihiko's, and her durability is a little bit worse. Still good for Middle, hates the weakness, lalalala.
Koromaru - Middle! Damage pretty close to Akihiko's, a much better weakness (Light, which could even be argued as ID weakness instead!), 2 resists (Fire and Dark, for all that dark isn't that great), also has High Counter like Junpei, and ID! He lacks healing of any sort, but has multiple options and back-up to help him. Also has great durability with his HP. The individual components could be better, but they add up to something pretty respectable.
Ken - High Middle. ID is good (solid - better than Koro's, though a more common element if you see it that way), and he has healing. Damage is...not great, though he does have the ability to hit both defenses. He lives on ID and healing, though his durability isn't great (better than Yukari!). At least the rarest weakness of the bunch helps (Dark).
Shinjiro - Temp! Anyway, at worst a Middle, possibly higher. If you take him at the time he leaves, he has Power Charge and good physicals, and shitty regen, though faces much, much lower averages in general. Scale him up to endgame with skills and everything, and he's pretty good as well - Power Charge, God's Hand, much better regen, High Counter. He's also the only one with no weaknesses, and his durability is solid. Might very well be some type of Low Heavy.
Chidori - PUNY!!!! Actually an awesome one. A great skillset backed up with horrible, horrible HP. At least her defenses are fairly normal! Anyway, 50% HP Tetrakarn wins against poor fighters, and she has REGEN!!!!!!
Jin - Levels change him and Takaya a lot. Anyway, I'd say Lower Heavy echelons. Has damage variety and lots of status, as well as durability. Nothing else special, but...good otherwise.
Takaya - Higher Heavy range. Damage is fantastic, and he has Mind Charge. Great durability too, and ID that he almost never uses! Good overall.
Now, for the questionable people!
Minato - Godlike. No matter what. Not giving initiative...makes him more beatable, though he's still evil. Armageddon is awful, and he can wall just about anything. Granted, HP are low, and most personas have weaknesses to exploit. I'd be for ranking him, personally, but most will view him as unbeatable, so...
Fuuka - Puny. Awful in all regards, but the cast loves you if you take her into the averages!
Aigis - Higher Middle ranges. Hates the resistance/weakness she has a lot. Loves everything else! No magic damage, but the kajas and physicals with healing and nothing else to spend her SP on make her pretty good overall. Plus, Orgia Mode for fun finishers. Godlike, though somewhat lower than Minato if you take Fes into account - lacking fusions ruins Armageddon, but she gets everything else in the game, which helps!
Nyx Avatar/Spoilers - Godlike. Lots of forms to wear people down, then the Death form to maul everyone with Moonless Gown and Night Queen. Excellent.
