@Jura - you make valid points. I didn't elaborate it on it much, but I was only suggesting a set of minimal standards, and not that all themes should have to go through them, but if they meet the standard, they get singled out for better placement.
I do client work, so I know well the tyranny of these tests that favor an unreal minimalism (Note, I didn't mention Google's pagespeed test, which is among the worst, and mostly just silly), and I did not mean to imply a test would be for things that have nothing to do with the theme, like deployment considerations.
However, the tests I mentioned help make sure one is following best practices. HTML proofer just makes sure there's nothing broken. The others contain information that a subset of which could be created to say to users that a theme has a certain level of integrity. Webpagetest alone (currently the gold standard for performance evaluation) can tell us if a theme is missing files, like icons, if it's loading a lot of scripts in a non-performant manner, and that sort of thing.
And, I didn't mention it, but I think as a community, we should encourage best practices in accessibility. Again, only supporting the the good ones, not penalizing the others.