Instead of Ghosts becoming like other failed sitcoms and dropping its original premise too soon, season 4 should reveal that Jay’s ability to see the ghosts is a fake out.
He might gain the power to see ghosts in one episode only to lose this in the next, or this skill might last a few episodes before his transformation is reversed. Ghosts season 3 pulled off something similar when the series seemingly dropped Flower only to reveal that she hadn’t really ascended to the afterlife a few episodes later. Thus, I’m comfortably certain Ghosts season 4 can reverse this upcoming twist.