Toss up. If Leon catches Wilder on that glass jaw of his, he could win, but the longer it goes, the more likely it is he loses. This said, although it;s a competitive H2H matchup, Leon is light-years ahead of Wilder in terms accomplishments in the sport.
I think Wilder might be able to pull this one off. Spinks was a pretty small HW. That said, it's not cut and dried because Leon could bang some, so Wilder would find a pastry chef or soccer hooligan to fight instead.
both mediocre on current evidence, wilder for struggling with nobodies and facing 1 live opponent ever, and leon for beating up a parky's patient. on the amateur side though leon beats him hands down.