I've never understood why Vladislaus II of Opole, as a male line Piast and a (female line) descendant of Vladislaus I the Elbow-High wasn't logical choice to ascend to the Polish throne either after the death of Casimir III or that of Louis I of Hungary, for whom he was essentially a viceroy. With a POD during or after the reign of Casimir III, make him end up King of Poland.