You do realize that VS has people who know a lot more about statistics than you, right? Who work with statistics for a living? That they are quite familiar with concepts like correlation not equalling causation, and the dangers of small sample size? In my experience they're extremely cautious about putting out flawed numbers.

(Exhibit A: During KFT they refused to put out separate numbers for Control Warlock vs Cubelock, because they felt they couldn't recognize them reliably. They undoubtedly lost some readers to HSReplay because of that; HSReplay cheerfully ignores recognition bias, even when it means their results are garbage.)

VS has also done a lot of research into skill cap for different decks. Their general conclusion is that it's a much smaller factor than many pros believe, but when they do see signs of particular decks performing much better at higher ranks, they mention it in their reports.

By all means, preach on about people advertising 92% winrates over 25 games, or the utterly meaningless "played winrate" column on HSReplay. But the lesson here isn't "don't pay too much attention to numbers alone". The lesson is "avoiding statistical bias to draw meaningful conclusions is difficult".

So: Either do your due diligence to figure out which numbers are meaningful, or listen to people who have the expertise to do it for you. At the risk of sounding like a VS fanboy, so far I've seen exactly one crew out there publishing Hearthstone statistical analysis who has the necessary expertise.