Saying that something is "fair" is not the same as "everyone has exactly equal chance to win regardless of effort, skill, or strategy." There is a great deal of strategy involved in preparing a team that can get the turn order and timings right to maximize damage done to the event bosses, and doing more damage should give a greater chance of being able to get the last kill on the boss, that's just simple math. Want to do away with campers trying to time the last hit? Fine, lock everyone that's into auto-fighting for the end. This one-hit-at-a-time charade is not only nonsensical and time-consuming, it hurts everyone in the realm by making the boss fights take longer and making it harder to get the stronger bosses with greater rewards.