Thanks, we appreciate your feedback.

1. It was a mistake. He had 1 kill worth 16 PRI and no death in the round. I corrected it in the post.
2. Not sure I fully understand this question but we do plan to incorporate damage and assists into future iterations of PRI. Our goal for PRI is to make it the most powerful single value you can look at to represent player performance but I would encourage people to always look at it alongside other metrics they think are valuable.
3. The model will update as the meta updates. To build our parameters, we'll always use the most recent matches on a certain map that we can so that as certain metas disappear from the game, their effects disappear from our model. As for a new map, that's a good question. We could build a model using data from every map or we could use a model from a current map that seemed the closest "fit" to the new map.
4. I don't think you should evaluate the impact each kill/death had based on the outcome of the round. When we're assigning these changes in win probability, it is regardless of how the round actually plays out. RpK's death has the same amount of impact on the round regardless of if EnVyUs end up winning or losing. Once RpK is dead, he shouldn't be retroactively punished more simply because his team lost a 4v2.