Perhaps it's me but the primary flaw I noticed is that this is an attempt to use a de facto individual ranking system to measure performance in a team setting. You need to match the metrics/measurements to what it is you're trying to reward; as in - if you truly want to encourage positive teamwork, adding a dimension that measure performance of teams you participate in should be part of your review. You're essentially trying to rank apples by how much they taste like oranges.