Djinn edited into his Rondo of Swords topic thoughts on all the duelers, and they mostly look right to me. RoS is one of the rare games that may be more votable off reading an LP rather than playing the game, since hooooly crap in-game documentation in RoS is a thing. Now add in that if you survive a RoS playthrough, you probably have to play through the game again… ugh.
A few things that the DL makes weird vs. in-game: I'm not sure I can easily think of another SRPG where movement is quite the god stat it is as Rondo of Swords. High move means not only being able to attack multiple enemies at once, but also getting the drop on enemy mages before they blow you up, or successfully executing hit-and-run strikes. Low move means moving in near the enemy lines, conceding first strike, and hoping for the best. High move *and* threat range (True Arrows wtf) a la Ansom / Naji is insanely good, equivalent almost to a Bolting/Mire tome in FIre Emblem games. Now add in that battles are "scored" by how fast you complete them a la Valkyria Chronicles. Yeah, it's too bad that move doesn't mean more. Flip side, Djinn's assumptions of maxed skill levels skips the majority of the game where skill points seem pretty tight (from Einander's LP, at least, where he built Ansom quite differently between Route A & Route B), and he doesn't reflect a few of the character's issues that would theoretically go away by endgame, sort of (Galahad's insanely late promotion that is usually impossible to access, Elmer's crippling underleveledness on join, etc.). Oh well! Also, the Revitalize skill of "heal 300 HP to self", which got basically no notice from Einander (slows you down when you could be pushing forward, costs a slot, use your darn healer), ends up pretty badass in the DL.
The RoS cast is also funny in the DL thanks to having 10 mage characters who generally have HP ranging from "meh" to "bad" to "pathetic" but also solid damage. Magic counts as magic resist, too, so check out the MDef list - 10 excellent MDef characters, and 14 characters allergic to magic. So the result is a bunch of mages with scary damage who get run over by fighters, and fighters who are very tanky (especially vs. physicals) but have bad damage. Amusing.
Anyway, a very brief rundown of some plot-centric characters, and then a few other amusing ones, for my own thoughts (although again, see Djinn's topic for his more complete list):
Altrius / "Serdic" - Pretty good, probably the cast's best dueler. High Heavy. Arch Paladin has Revitalize / Vital Power / amazing defense for stall-spam - 393 RoS HP is .94 raw PCHP, which ends up as an effective 1.57 PCHP of healing a turn vs. physicals thanks to his defense, which is ludicrous. Cold Emperor has a pile of HP thanks to Invoke Life, a shockingly relevant 10% HP regen, good damage, and Seven Sins as a nasty finisher if a battle goes long vs. a healer. They both have the wacky MC increase trick to deal with status-slingers who are either slower than average speed or whose status is turn 2, and Arch Paladin has Angelic Word to screw up even fast turn 1 status. His damage is okay for Heavy but not amazing, it's mostly the incredible tanking that's going to win him matches (if held to one form, he probably wants Arch Paladin, actually). Be a mage with badass damage, or have some infinite buff / healing trick, if you want to beat him; Altrius only really fears Zerase types.
Marie - Puny. 0.27 PDurability and infinite healing, even the low-damage types who don't OHKO her heal-lock her then wait for a double / critical hit / something. Can deal with Puny Mages, maybe, though!
Aegil - Low Middle? Mages have authentic trouble getting damage to stick vs. her, and too many fighters in Light only 3HKO her, which is death. She minorly spoils archers and status-slingers too, but gets spoiled by holy resistance or MP-busting (she doesn't have infinite MP like Marie, but she does have a lot of it).
Igraine - Cosmically bad vs. physicals, Igraine is still better than Marie because she actually has good damage and even better magical defense, and thus solidly spoils Light mages…. well, pure mages. Fast mages with any sort of physical fallback that doesn't totally fail crush her anyway! Low Light.
Less plot but interesting:
Margus - Altrius's brutal infinite stall game, except with no damage and no status resistance until his turn (although he can go immune after). Low Heavy, like FF13 Sentinel Snow without a Summon to build into.
Arios - Somehow Heavy despite the awful HP & Defense. Emitting a OHKO every turn is pretty good I hear. Most lopsided stat build in the game, all the damage, gamebest magic which means gamebest magic resistance, gameworst defense, and amazingly awful HP. He can outslug *Godlike* pure mages with that resistance, and plenty of good fighters who are nevertheless slower than average will get nuked first in the race for the OHKO. Probably the 2nd best dueler in the cast. Funny.
Izuna - Invoke Life / Vital Power for a pile of HP & regen, Angelic Word for status, and a powerful Overbreak she can even access faster if she gives up her damage (although 1-range-at-start-of-turn means respecting it less vs. ranged enemies). Kind of like Cold Emperor but with much worse defense. Low Heavy.
Naji - Djinn, RandomConsonant, and I talked out Bravely Default Performer vs. Naji in chat. Performer probably wins, which considering Performer's performance in the Puny Proving Grounds should really say it all. (they both give each other lots of time, Naji to get criticals off his high 37% rate, Performer to increase her stats off Buff Up + Support Amp… but Naji probably needs ~8 shots to kill, while Performer should kill in 7 actions + finishing Brave Blitz, and will also be increasing her speed & defense the whole time. So Naji needs to get 3 crits out of 6 or something. An amazing Puny. (read Einander's LP! Despite being worse than Ansom, Naji actually has a real niche in-game, where enemy mages are made of paper but are deadly, so Naji's okay-for-a-fighter magic and super-long range make him good at mage-sniping.)
--
Also, since I was digging this up for other reasons, a guide to Tactics Ogre characters and the DL, with the focus more on "sanity for voting" rather than division rank. Here's who's in TOPSP with the disclaimer that even those on all-routes are all missable if you get them killed before join (except for Olivya of all people, I think):
All routes:
Arycelle, Canopus, Donnalto, Gildas (L/C)*, Hobyrim, Mirdyn, Olivya, Sherri
Warrior Denam, Guest Catiua
C2 & C3 boss Vyse / Leonar [stats might change somewhat but not hugely]
C4 bosses
Splitpath:
Bayin (N/C), Cerya (N/C), Cistina (N/C), Dievold (N), Folcurt (N/C), Jeunan (L), Ocionne (L), Oelias (N), PC Ozma (L), Ravness (L), Xapan (L), PC Vyse (L)
Lord Denam, PC Catiua (Priest & underlevel Princess), boss Catiua
Postgame and/or ridiculous FAQ-bait:
Azelstan, Cressida (C), Deneb, Ganpp & pals, Lanselot, Lindl, Iuria, Rudlum, Warren; also Shaman Phoraena sisters & PC Dark Priest Catiua
Named generics, yawn:
Chamos(N), Ehlrig (N), Felicia, Phaesta (N), Sara, Tamuz (N), Voltare
Nobody plays only Neutral so Gildas seems safe to stick in "All routes".
A few of these are touchy; Ravness / Sherri / PC Ozma / Cerya-in-Neutral recruitments are FAQ-bait but they're plot relevant; Ocionne joins super-late in Law but at least is theoretically ready to go on join if you previously leveled Beast Tamer, while Lindl, who also joins super-late in the main game, has Fusilier guaranteed to be level 1, making me lean toward it being postgame.
Additionally, Lord Denam is a bit wacky in that Lord's big advantage is the ability to use a ton of normally other-class exclusive skills like Phalanx & Double Attack. However, Lord doesn't learn these skills itself, although the cost to buy a Knight's Classmark early and grab Phalanx at least is pretty trivial (if you know to do it, since the game only gives you 1 Classmark, sigh). It is still a pretty unique niche, more so than say the Fire Emblem Awakening Avatar or Morgan having full mix-and-match skill access in the aftergame, but another headache for the interp.