MMR decay
This is the same thing I am wondering. There should be a few things.
1) Higher minimum game play requirement
2) MUCH Faster Decay
3) The MMR should go off of your opponents CURRENT MMR every hour when it’s configured, not the MMR they had at the time you played them.
For the system to work, the decay needs to force everybody to play to maintain their rating.
By forcing people to play, the volatility will decrease and the deviation will become easier to calculate (deviation formula gets more accurate the more matches you play), which in return will make the whole system more accurate, because you can not just sit on your deviation rating and shoot back up after 3 months of not queueing, as the system is only affecting your current rating currently.
Rating and deviation are both critical to how much rating you gain or lose after a match. We need a decay for both and it needs to be harsh, because your rank is currently the only meaningful reward in PvP.
If rating was influenced by some kind of regular prize pool tournaments that would encourage players to actually participate, it’d be a totally different story, but since that isn’t the case, preserving your rank and your deviation to earn the biggest reward (your rank) is simply a reality.