At 140 Maidana wasn't anything special. IMO people are overestimating Maidana after his Broner, Floyd, and Morales fight. Maidana has power but he also has fought a lot stiffs and not a lot of boxers, in fact losing to Devon Alexander and Amir Khan who both outboxed him. Additionally Maidana wasn't iron chinned or body, he's been visibly hurt in several fights but has good recovery abilities. Loma would outbox and out maneuver Maidana until the KO or a wide UD came.
Not a good fantasy fight IMO, but still some interesting things to think about. Maidana gave Floyd issues; Floyd solved those issues, but Maidana presented enough to make me think that he'd give Lomachenko real problems at 140. Don't know if Loma would be able to hurt him except by landing full-power combos; to do that he'd have to stay in range, and it might be hard for Loma to avoid getting hit by one big shot when his opponent's fine with getting hurt. Still favour Loma 65-35, because he's still a genius, just don't think it's a blowout if Maidana has good mental discipline.