Here's an example of metrics I was thinking about on a game by game basis. Curious to know what others think. It could be stored with custom tags in the PGN. I believe this could help spot areas of strength/weakness (in a particular stage of the game, in a particular ECO or as white/black) and to track improvements overtime.
We can also use a rate of occurrence for the move rating. Such as, x% of all moves are a blunder. Or, X.XXX blunders per 100 moves.
Not trying to focus on how the metrics are calculated: what metrics do you find useful?

I'm getting more into the habit of analyzing my games and following up with reviewing analysis from a chess engine as well.
I'm very interested in a few aspects of the game summary that lichess.org provides: 1) number of inaccuracies, mistakes and blunders, 2) the line chart of the engine score, and 3) average centipawn loss.
Is there any software that includes tracking of game metrics like this? This could easily show my progress over time, as white/black or even when playing a particular opening. It could hi light some weaknesses.