Someone who intentionally steals someone else's GF or wife, scumbag, plain and simple. But imo a "complete scumbag" would be stealing someones girl, fucking her, but then tossing her aside or passing her around to other guys once he's had his fill. That's kinda what I assume Fujino means by Inoda not being a "complete scumbag". Inoda clearly wants Asuna for himself, and doesn't want anyone else touching her. As we saw he's even holding himself back from lashing out at Kirito cuz he knows he has to play the long game if he wants Asuna to be exclusively his. There's definitely levels of scumbaggery, and Fujino is clearly not wanting Inoda to be the lowest of the low, but he clearly does view Inoda as a scumbag, just not a "complete scumbag".
I mean, the dev has already admitted that he failed in portraying Inoda the way he intended initially.
The point is, whatever he does now in part 2 doesn't change what happened back in part 1. He could turn him into the nicest person on earth, but it would just contradict the logic set by himself for the game. imho, I think Inoda is a perfectly fine character as he was in part 1. He should either keep him that way or even build upon the scumbag narrative. There is no logical reason for changes, as Inoda has a personality with no regrets or hesitations. I would even say he is bolder now, after that rage outburst and wish of killing Kirito.
As for his relationship with Asuna, he is now even more maniacally obsessed with her, seeing her as his property after the rainy night. The whole 'nice guy' act is just because of Liz, who is more or less forcing him to play along, but he clearly hates it. Hmm, maybe he could go a weird love route with Inoda to explain why he is nicer to Asuna, but there is no buildup to that as for now, and I have a feeling that the audience wouldn't like it.
In defense of Fujino, it's much easier to depict simple good or evil characters. Going down the layers of complexity requires a fine understanding of human nature. It's his first attempt to create deeper characters, and it's fine to make mistakes.