I don't know who would win but I'd rather Loma's economical defensive skills over Whitaker's flashy defensive skills. Loma has very good positioning and footwork with minimal movement in defense. Very plain and effective.
Good match up. Loma throws more and misses while Pea clowns and slips. Pernell's deficiency in landing meaningful punches makes it close. It becomes a battle of footwork leaving onlookers divided. Whitaker SD12 Lomachenko
To be fair to him, 3 of those losses were right at the end of his career, with 2 of them being against prime versions of Oscar and Tito.
Although he was superb against Commey, in general Lomachenko hasn't impressed me as much at Lightweight as he did at Feather and Super-Feather and I think he peaked at, or was better-suited to, those weights. I think at 135 Whitaker is favourite here and while Lomachenko is no doubt gifted, here he'd be running into one of the few men who is in the same kind of bracket in terms of pure boxing ability and trickery. Competitive fight, maybe not a great one to watch if you're not a purist, but I've got Pea by decision here.