Criticality in workflow might also be a consideration. I'd have to check how homebrew does this, but Debian frequently has separate documentation and debug packages as supplements to core functionality. Those might be essential in cases.

Since homebrew is aimed mostly at technical types and devs, build tools themselves are probably fairly highly featured, but those are easy things to lose in large general-public releases. (Android's abysmally poor shell tools come to mind.)

Sounds like a pretty good basic set. The flaky builds criterion in particular seems like a strong signal of a low-quality upstream.