Asvel, Homer, and Nanna can use staves but they're not good because of the staves so I wouldn't group them together.
Fergus is not only good in manster he can also be a key combat unit from ch8-14, especially if you aren't relying on asvel.
Lara is easily one of the absolute best units in the game, dance opens up so many new strategies and even in its most basic use it's giving your most valuable unit a second turn.
Karin, eda, lifis were mentioned earlier.
Othin is a killing machine due to wrath and the pugi plus he's relatively durable. He's a strong combat unit in the early-midgame and potentially a candidate for training into the late game.
Although I've said that Leaf is a "support bot", when you're finished with Manster the only significant supports he gives are to Fin, Asvel, and maybe Linoan. That's nice but I don't think anyone claims Tanya is good just because she supports Othin and Dagda.
Most units in the roster have their own distinct advantages but it's not hard to judge that some are more valuable than others. Even shannam has his own niche in his bargain skill but that's obviously not enough.But it really doesn't matter how you rank units, we probably agree on how to use these units and just have different ways of ranking them. I just want to ramble on about thracia characters>>519253>dragon lance
Rather than using rescue I recommend using sleep on the boss, that way you can loot that entire part of the map.