re:Dude
Athos has endgame FE stats at the start of the dungeon. In his case, physical attacks do little, magic attacks barely scratch him. To boot, Floor 1 isn't generally dangerous anyway. And, I'd note. Bolting damage off of endgame FE stats for floor 2 is still going to be very, very painful. Then counter hype starts on Floor 3.
Yuna: Fast, evasive healer with loads of magic defense by the end. She can null elements for the party (covering for P3/P4 characters especially) and has a generally decent support set. Getting Holy just makes it that much nastier.
Ryu 2: Yuri 1's FTC isn't quite the stupid overkill that Ryu-2's G-Drgn is. On top of that, you're neglecting to mention that the guy's got infinite healing (though hahahahaha to that ever being hyped), some healing earlygame, and a notable physical game--early, at least, though I've seen that aspect be taken advantage of to kill the living shit out of the final boss in record time.
Blue Mage: I'll give you that Bartz gets the whole thing faster. Bartz does have the unholy position of being a project character, though, can only really take advantage of the abilities of a class if one of its skillsets are equipped, and thus requires constant thought about what to do for each class. Blue Mage, at least you know what you're getting. And the skillset IS from hell.
Sarah:Interp issues ahoy with Shining Force characters, and that aside, she's a healer with an arguable not-completely-fail physical later. She's fine where she is, really.