Have you considered... Asking? Asking why you are doing something? All of these changes are going to have a purpose behind them, and at least in these examples those reasons are likely to be things a dev is in a position to metric the results of themselves. How much throughput did you add by switching to Flume? How much did you reduce bandwidth with that binary format? Even if you don't have access to the production metrics (and most places you will) you could estimate based on synthetic data.

Even for product work I've yet to meet the product person who isn't eager to talk about how a new feature was received when a dev asks.