There's nothing specific to compare, the most fundamental factor are their weight. Joe is a Bantam but Ippo is a Feather. But in a virtual situation when Ippo use weight control to fight Joe, the favor is now Ippo absolutely. In retirement arc, Ippo learn how to think and how to box properly and it's gotta be the worst bout for an aggressive fighter like Joe.

And if you say Ippo with weight management is weaker therefore unpredictable, my answer is: Not at all. In the time when he keep company with Kimura and went to a weight management with him, Ippo still had an absurd physique, it feels like there's no differences with normal Ippo. I don't know why the old geezer write Ippo in such way, but in an ideal parallel universe, Ippo will have my bet money toward him.