Final Fantasy Tactics Generics:
Squire: 7.5/10. Gained JP Up is ridiculous, and really saves a class that would be otherwise probably in the 3/10 range even with Move+1 (and 0/10 without).
Chemist: 7/10. If you're really playing optimally (like Summon Wizard) you actually don't touch them that much. 90 JP Phoenix Down does outclass about 65% of skillsets, though.
Knight: 3/10. Decent early (I know people who swear by Knight Delita for SCCs that can't handle early fights). Weapon Guard is good. If my mathskiller is a generic, I'll sometimes use Excalibur CT5Holy, depending on speed requirements.
Archer: 3/10. Part of the Concentrate Ninja package; one of about three viable routes in optimal play.
Wizard: 9/10. MAU. Crazy MA with the right equips. Black Magic is excellent early, and still useable late.
Priest: 5/10. Mostly useful with Math Skill.
Monk: 3/10. I'd call early Delita Monk the best way for say, Calc SCCs to get through Chapter 1 (some would argue Knight or Summoner) but that's about the only place I've really found core Monk optimal. That said, Martial Arts Ninja is enough to bring this up to 3.
Thief: 2.5/10. Is Move+2 Ninja enough to bring this up to 3? Ehh...you know, I'm going to kneejerk a little lower--Move+1 Ninjas would still handle rescue fights and speed-necessary fights that give calcs trouble like the roof just fine, and Teleport Ninjas are arguably better than Move+2 Ninjas, despite the Throw bonus. (And I'm not feeling that generous towards poaching today; needs to combine with Mediator, and it's a 33% chance of Uribo anyhow).
Time Mage: 7.5/10. Lots of good stuff like Teleport and Haste; even the record math skill speedrun uses MP-Switch to allow you to Holy self. Countermagic Quick is really abusive. Usually not the focus, but it's hard to think of good strategies that don't use them at all.
Oracle: 5.5/10. Above or below Priest...hmm...YYM >>> White; I've actually chosen it over Math Skill on a solo challenge (and chosen it over stuff like Summon and Item in non-zodiac fights). Move MP Up > yeah, Priest has nothing here. So do I give White credit for breaking MS more than it would be broken? Nah; I'll be consistent in being relatively harsh on "I'm the weak half of this combo".
Geomancer: 2/10. Attack Up for Swordskillers. And on rare occasions Ninjas.
Lancer: 1/10. Jump is cool to avoid spells. They're just...a dead end; there's nothing that's worth the cost when playing optimally. (Now, if Math Skill were more expensive...).
Summoner: 9/10. Wtf Shiva/Ramuh/Ifrit. Wtf.
Mediator: 2/10. In keeping with my not feeling generous towards poaching today...yeah, what else do they have going for them?
Ninja: 6.5/10. They fill a niche left open by summoners/mathskillers, so there's at least three viable setups in an optimal party. Certainly the weakest of the three. But...is there an alternative? Nothing else has speed.
Samurai: 2/10. On the one hand, they take about as long to get going as Math Skill, and are worse, and can't get going until later chapters because of what's not storebought. On the other hand, they tend to come out in the endgame anyway; especially near level 99, they're just obviously the #2 alternative. Umm...this feels like poaching, which you will use at endgame, but takes time to setup and can't do much until stuff unlocks in later chapters. What did I give poaching? Let's copy that score.
Calculator: 8/10. The number of classes that said "takes as long to get as Calc, and worse, therefore not good." ...yeah.
Bard: 1/10. Angel Song is cool on paper for like...Ramza, probably as he trains in Calc.
Dancer: 1/10. Nothing breaks Chapter 1 like Dancers; not even Mathskillers. <3 Dancers
. I can't really claim that this is a useful niche, but it is a niche and it's hilarious, and that keeps them from 0.
Mime: 0/10. I've written essays about how they suck much more than even previously suspected. Level up-down use is a niche, to be fair, but not enough to keep them from 0 for me.