I believe it’s because the current matching system is terrible.
Now; Matching systems in gaming are really not my area of expertise, but I can only assume that the current system is some type of ELO based matching? Having been a chess player for many years, I do have some knowledge of that particular system, and assuming that is what is used in HS, I have to say this particular version is terrible. Small wonder so many players think it is rigged. I cannot offer any suggestions to fix it or change it, because I do not know what other systems are available and I do not know enough of this particular system to offer constructive advice for improvements, but I can say that I wish Team 5 would seriously consider the current matching system for review and possible revisions.
Hope I don’t agitate anyone for saying what I think.
Oh boy Mall. Here we go. 
Every competitive game out there has players claiming the system is rigged. Is the video game industry as a whole unable to make a decent matchmaking algorithm?
I don’t know. I just question whether there is a better system than the one We currently have?
I think that if Blizzard thought there’s a better matchmaking alternative it’d be in-use now. But maybe there is, it’s not impossible. I know that many really hate the current iteration, for sure.
I don’t know that’s true. Companies usually go with the cheapest thing they can get the job done with.
Would changing the algorithm really cost a lot of money, though?
Again; I don’t know. But i think it’s fair to consider whether there might be a better system that players maybe would not complain about so much.
Oh, I agree definitely. Although, there will be hate no matter what.
Probably not. Matchmaking algorithms are a pretty standard part of online games, and this one in particular doesn’t even have to worry about the issue of teammates.
Truth is, people complaining about matchmaking is more often than not a consequence of the Dunning-Kruger effect. The D-K effect states that people who lack competence in a particular area also lack the necessary knowledge to evaluate their competence in said area. If you are a mediocre Hearthstone player, your estimation of your own skill is probably less accurate (and likely inflated) compared to a top-level player, simply because you don’t understand the game well enough to know how little you actually know.
And this, in turn, feeds belief in rigging because your opponents seem to have perfect draws (they don’t, they’re just better at knowing when to maximize a card’s impact), or you always run into “your counters” (sometimes, other times you just run into a deck you don’t know how to play against).
On an unrelated note, your estimation of the quality of the matchmaking system seems suspect, since (as you admit), you don’t know about the specifics of the system, nor do you know about alternatives. If you don’t know the specifics of a system, nor do you know what other systems are out there, how can you know the current system is bad?
And don’t say “because people complain about it.” People complain about a lot of things, even perfectly good things, because they can. It doesn’t make the target of the complaint objectively bad.
People complain about it being rigged because they are freaking idiots, end of story…
That sums up a lot of Max’s post. 
I was trying to be diplomatic about it 
I (personally) dislike the system because it feels bad to constantly face (for instance) the same class, same deck, repeatedly when there are millions of players online at any given time. Is this really the best HS can do with such a large audience playing?
Or; is the player base not as large as i am imagining?
Random matching certainly has it’s limits if the first is true, because I regularly face not only the same decks/classes, I have faced the same player repeatedly and on more than one occasion.
I just think reviewing the current system isn’t a bad idea.
That’s because, I think, class is not taken into consideration in matchmaking. And it’s probable that certain classes are at a higher pick rate in certain MMRs and ranks. And in general.
I’ve often wondered if the speed of the matchmaker isn’t a factor.
I myself would gladly wait a bit longer if it meant that i could have more diversity, although I am not sure anyone else would feel that way.
You need evaluation criteria before you can ask that.
How do you know the matching system is bad? What does good mean?
I know exactly why some people cry “rigged”. It’s because they don’t understand how math works.
The more popular a deck is, the more likely you are to run into it. This is true regardless of how many people are playing the game.
You could change the matchmaking system to address this, but I personally don’t think it’d be worth it. You’d end up with a more varied matchup spread at the cost of longer queue times and greater MMR spread between players, both of which (IMO) are less desirable than having to face the same handful of decks.
So I am partially right in that the speed of the matching plays some role in the opponents We face?
I wonder if some happy medium isn’t possible between speed and diversity of matches?
i do understand that spread in MMR isn’t desirable as well.
I think that longer queue times would be the result, but i don’t really see that as a deterrent, although many would, I’m sure.