5. The fight with the Saviors might cost Morgan his sanity
It was obvious that Morgan became a bit unglued this episode, and as cool as it was seeing him just letting loose on Richard, it was likely also a sign that he's slipping back into his Season 3 frame of mind.
Twice in Episode 13, Benjamin quotes The Art Of Peace to Morgan, telling him "to injure an opponent is to injure oneself," and by the end of the episode Morgan's injury to himself through ending Richard's life was already evident. After killing Richard, Morgan began to explain Richard's initial plan to Ezekiel, except instead of saying "Benjamin," Morgan called him by his dead son's name, Duane.
After Duane's death sometime between Season 1 and 3, Morgan lost his mind. It was only after Rick's visit in Season 3 that Morgan began to clear his mind, ultimately becoming Eastman's student, and using Aikido and The Art Of Peace to save himself, even after Eastman died. But now that Morgan has diverged from the belief system that was keeping him sane, it looks like he might be sliding back to instability. The final scene, with Morgan on the cottage porch sharpening his Aikido jō, seemed to confirm this, with hints that Morgan was planning to use the jō as a weapon or protection in the same manner he did way back in Season 3 when he was so crazy he stabbed his one friend, Rick.