A long-winded intro, but I don’t see it getting to the point.
What OG is talking about is, essentially, the outcomes in single games being decided by random effects, rather than the player’s choices and thus their skill. How it pertains to Hearthstone, I think, is obvious enough.
I’ve written a bit, somewhat sarcastically, about the impact of skill myself, and I can offer another example: in chess, you’re likely not gonna beat a grandmaster unless you are on a high enough level; on a boxing ring, you as an amateur are gonna get smacked by a pro athlete; in HS, however… well, you know, don’t you?
There’s also another point about estimating overall risks and odds over a large amount of games, random outcomes taken into account, hence the analogy with poker, but that’s another thing, which, by the way, OG also discusses, and I don’t see a contradiction here either.
PS What you speak of about opportunities essentially translates into the difference between, say, 49% and 51% win rates long-term, but that also fits the overall picture.
One more thing I could add to this is the following: if you’re after a strategic, so to speak, chess-like play style, meaning that you calculate your opponent’s possible moves and plan your responses, then wild ‘RNG’ effects completely destroy it, making the game unpredictable. Whether you can speak of ‘skill’ in such scenarios is a matter of word choice, I guess, but I’d say it’s a different kind of skill than described earlier.
In the end, there’s nothing wrong if someone wants to play a game that is more like poker or even roulette, as opposed to chess, but I do agree that Ben Brode’s ideas about ‘variance’ are a bit… strange, as were, in my opinion, some of his ‘BWAHAHA’ design solutions in HS, known as ‘RNG monsters’ (well, by modern standards it might be laughable, so it’s relative, but that’s another story).