Heavy:
Alena (DQ4) vs Nina (BoF4): Nina4's only real flaw is her durability, and thanks to her physical resistance this is easy to prop up with the right masters if you care. She's just so versatile and so hard to match, her leads in two crucial stats (AP and Speed) are huge, and her innate skillset is just the best (healing + wind magic) except perhaps Ryu. Alena feels like there's less good you can say about her, since all she does is smash 1-2 targets. She's amazing at that, but Nina isn't bad either (needs Ursula to make her randomsmashing truly evil, only real downside) and has more going for her overall.
Middle:
Angelo (DQ8) vs Aika (SoA): Sounds like Aika deserves this one. Angelo is good but I think people are remembering the part of the game where Multiheal both exists and is useful to be longer than it actually is.
Light:
Tim Rhymeless (WA2) vs Massimo (MMXCM): First Aiding his way to the title.
Onix:
Adam (SF1) vs Mime (FFT): If you actually unlock Mime, then, bad as he is, he can do things nobody else can. You can set up some double summoning or dancing or... something. Adam just lacks any use whatsoever, you have to actively waste large amounts of time only to get someone who does something that most of the cast can do by that point (kill single enemies with physical attacks). Truly a deserving finals for the Onix division. Actually, no. Onix is shamed by association with these two.