Before Inoue retires? He has stated that he will compete at Featherweight by 2025 and then finish at Super Featherweight.
And does being Undisputed at 118, 122, 126, titleholder at 130, and retiring undefeated make him the GOAT?
No but if Rolando Romero can grab hold of a belt then I wouldn't be surprised. These hypothetical questions depend on the quality of the champions at the time. Look at how weak middleweight is right now for example. I've always said that Inoue will max out at 126 and will struggle at any weight above that.
He is 10 cm shorter than Mike Tyson. That's less than an iPhone. With the right nutrition and training plan, yes he can move up in weight easily and even win a title. He has the natural power, speed and dedication to the sport. He's a fighter. People look too much at weight as if a small guy can't hurt a bigger guy. These people have never sparred against smaller guys. Punches still hurt if they connect.
I think his strength will carry into higher weight divisions, especially with the right workout. If you have natural power, it becomes stronger when you move up. I am not exaggerating if I say he probably hits harder than for example Sven Ottke.
Even though Loma is tiny for 135, is completely maxed out at that weight, and all those guys he's fighting up there are way bigger and heavier than him, do I believe he could win a title at 140? For sure. I mean if he's already able to beat elite supposed P4P talents at that weight like Haney (albeit obviously he got robbed) who have 20lbs and almost 6'' in reach on him when he's well past his best then surely he could pick up a strap at 140 in his prime. Haney weighs more at 135 than most of those guys do at 140. Regarding Inoue being able to win one at 135? Well first he has to prove himself at 126 and 130. His 126 could be Loma's 140 or it could be Loma's 135 and 135 for him being as far as he can go up before size beats him.