I think the best way to reintroduce Jean Paul would be to have the recently deceased Amon Sur's Sinestro ring recruit him. He was built as a weapon of fear; he's perfect for the ring. The ring would attempt to bring him to Qward for conditioning, as with all Sinestros, but Jean Paul would resist and seek out Batman for aid in ridding himself of the ring. When the Sinestro Corps tried to recruit Batman, he was able to override the ring with willpower, but Jean Paul was always weak-willed, which is why he so readily submerged himself in different identities and philosophies, unable to really decide what he himself wanted for his life. I think I neat idea would be for Jean Paul to undergo the same seven-week isolation ritual Batman underwent during 52, as a means of finding his own identity to help him shake off the ring. The best part is that Jean Paul's system-induced delusions would probably manifest through the ring during such a ritual; he'd find himself facing walking, talking ring constructs of St. Dumas, his father, or even himself as Batman.
