Apologies in advance; I don’t usually write long texts in English… I might have to ask ChatGPT for help!
That said, let’s talk about the MMR system. By now, I imagine most players in PvP have at least a general idea of how it works. In short, MMR (Matchmaking Rating) is the number used to place you into a lobby. If you win, your MMR increases, and if you lose, it decreases. After a match, MMR is recalculated, and your CR (Combat Rating) gain or loss is determined based on your new MMR.
Now for the interesting part—the intended and unintended mechanics. The MMR system is essentially an “economics” problem, one without a perfect solution—just theories and speculations. Why? Because MMR acts like a currency. While you don’t “buy” anything with MMR, you do gain or lose it through PvP matches by winning or losing. This means that MMR is in a fixed pool—it’s not a hard cap, but Blizzard designed it with a progression in mind. When you win, you gain a certain percentage (X%) of the difference between your MMR and the average MMR of the losing opponent’s team, and when you lose, you lose a smaller percentage (Y%) of that difference. The fact that X is larger than Y creates slight inflation, which gives the feeling of progression, even at the highest levels (though I’m not rank 1, of course!).
If Blizzard says they’re adjusting the progression curve, they’re adjusting this percentage. But why is this an unsolvable problem? Meritocracy! Better players will take MMR from less skilled players. It’s similar to that dystopian movie with Justin Timberlake—some people live forever while others must die young. It’s not a great analogy, but bear with me. Players can only take MMR from others within their MMR range. So, a player with 1800 MMR will only face opponents in the 1700–1900 MMR range, and if they drop, they need to climb back by taking MMR from their new lower range. On day one of a season, everyone starts with 0 CR but 1500 MMR. So, every active player in that bracket has the same starting MMR, creating a pool of MMR for that season. Of course, people leave and join, but that’s the basic setup.
If you can only take MMR from matches within your range, and if there are different win/loss calculations for each range, that might explain why rank 1 players feel like their CR is capped. Blizzard’s solution is the inflation system. Each week, the system gives players an MMR boost (e.g., 100 MMR), which explains why if you join later in the season, your character starts with 2000 MMR instead of the 1500 your main had at the beginning. This inflation system helps rank 1 players reach 3000 MMR and makes average players feel like they’re progressing since they’re winning against higher MMR opponents and gaining more CR. It also increases the total MMR pool.
Why doesn’t Blizzard just raise the starting MMR so players don’t feel stuck at a rating without rewards? For example, if rank 1 is 2800 and most players are at 2100, why not just boost everyone? The problem is that, as I mentioned, the system relies on participation numbers to define the MMR pool size. In the first season, Blizzard doesn’t know how many players will participate, so they can’t set the reward difficulty accurately. Too easy, and people quit early; too hard, and the same thing happens.
If the inflation system works, why not give the full amount of inflation upfront, like adding 600 MMR in one go instead of spreading it over six weeks? Because then top players would hit their ceiling too fast, leaving everyone else feeling stuck. The gradual inflation creates a sense of progression.
As for why Battleground Blitz is different, it’s because the MMR pool size (like the money in a poker game) is larger, and the win/loss rate calculations haven’t been tweaked yet.
In conclusion, I hope I’ve explained my reverse engineering of the MMR system and its issues clearly. My humble suggestion: avoid using a currency-like system to organize and reward PvP. Instead, consider a simpler system, like a badge system where current achievements (Combatant, Rival, Duelist) are badges that you can gain or lose by winning or losing a set number of matches, so if you win N matches witout losing M matches you go up a badge, if you dont you go down.