I wish he had fought more top guys than Carlos Ortiz, but overall he has a very strong argument for top 100p4p. Avenged all his losses and beat Carlos Ortiz 2/3 times. Became champ of a weaker division due to questionable legitimacy of 140, and for a short time. Hot take: he's better than Aaron Pryor
There's very limited footage of Duillio Loi sadly. Would have helped if he had fought Nicolino Locche. Based on the style that described Loi (an aggressive and awkward pressure fighter but without the punch) he might have been able to beat Locche.
I don't have a strict top 100. But yeah he'd probably make it atleast. There was a good thread years ago comparing him to Calzaghe. Read it for some great info.