I can't even enumerate all the messed up consequences for making GNW rewards distribution automated.

I can only say that you should've just consulted with your leader and come up with an organized rotation of rewards.

GNW is based on teamwork, and just as most other group-oriented activities are, it's composed of both objective and subjective deliberation based on the goals and the outcomes. You can't just merely rely on an automated system to make rational decisions unless you come up and design a near-perfect AI script that could mimic a human's decision-making.