Many times, I've partied with players who don't understand positioning, or don't have the necessary feedback to learn these jobs. With some simple changes, the game can offer a better learning curve for new players and give better responses for the experienced as well.

Suggestions

1. Fly text saying "Rear hit! or Rear hit success" Additionally, it could detail hits, like "Dragon Kick 200 + 150 = 350" flanked.

2. Audio cues: customized sounds to alert the player.

3. An option that changes the color/complexion of a mob's ground circle based on relative position. A line or arrow could also connect and denote which side you were on.

While mostly for new players, having visual and audio cues to allow players to better know when they've successfully hit a rear/flank attack would help people learn more quickly as well as provide utility to even the experienced.