Since you guys seem to have never done any research into this yourselves, I'll educate you on the topic of rating/elo decay and why it's good and why it's bad. So first of all, why is it implemented?

The main reason is that if someone gets a super high rating and then stops playing. So why is that a bad thing? Let me take Rocket League, a game that I have been playing a lot lately and show why it's important. In Rocket League Season 1, the ranked leaderboards were dominated by SARPBC (the predecessor to Rocket League) veterans. As a result, there was a huge disparity between SARPBC veterans and new players. All the SARP vets were way higher rated. However, there was one player (a SARP vet) who stopped playing. His rating was super high because the SARP vets dominated the leaderboards. Then, the new players got better, climbing up and matching the SARP veterans skills, lowering the ratings of all the SARP veterans. The guy who stopped playing then came back and was significantly worse than all the other players but was still rated the highest because of the change in the meta.

Now onto the next part of this; how could anything like this occur? Why would the median elo change, seemingly randomly? It's simple; new metas or change in the player base size. Elo works with inflation; the larger the playerbase, the more it's inflated. The more it's inflated, the higher rated the highest players are and the lower rated the lowest players are. Makes sense and there are no issues with this, right? Not quite. Let's say that the playerbase size decreases. If that's the case, there is less inflation. So if the playerbase is huge and then someone hits 3k elo and then the playerbase gets smaller, 3k elo may not be achieveable anymore because there is simply less inflation.

Next, I'd like to address the issue that is "what if someone can't play/stops playing?" Well that's the point. It makes it so that to maintain your rank (whether it be the highest on the server or just some average rank) you have to keep playing so that your rank is always adjusting along with the inflation. It's also worth noting your skill fluctuates. Having elo decay makes it so you can't just say "oh I'm playing really well today" and become 2k that day and then never play again, it makes it so your rating is more reflective of your true skill level. In that regard, elo decay isn't bad.

Now I'm going to address what I think about this implementation; it's stupid. Despite all the defending I've done for the system, it's not a good move for Badlion, and there are a few reasons why. Firstly, seasons are short enough that they effectively act like elo decay and they are hard resets. They make it so you can't sit on your rank forever and actually have to play to maintain a high rank. Secondly, I don't see the playerbase size having enough of an effect on inflation as I think that it's fluctuating but has remained stable for the most part. As well as this, it's only a problem if the playerbase is shrinking, and I'm not entirely sure if it is but I don't think it is to a significant level. And lastly, change. Large changes to a system that has been proven to work (season 12 was phenomenally fun) aren't going to help it; they will hinder it. Badlion isn't doing the best, at least to my knowledge. There are certain things that have been happening for seasons; getting a high rank and then just not playing because you reached the rank you were going for, grinding global by queuing any kit, etc. I think if anything Badlion needs more of that nostalgia in terms of Arena than to try and make more and more new features that I don't think are applicable to Badlion as a server and will in general lose players because they're straying from the original nature of Badlion, one of the things that made me stay for as long as I did.

Lastly, I'd like to address the optimal way of having a rating system; fuck off. Doesn't exist. It is subjective, for each and every case it is different. The way Badlion is structured with a small player base and matches being quick to go either way, it doesn't make sense to use a system like MMR when all that we're going to do to MMR is try and make it more like elo. In a similar way, elo decay is the same thing. Elo/Rating decay is great for so many cases, but this isn't one of them. I'm no expert on this; I've done my own research and am hugely interested in the topic, but from my albeit limited knowledge, this is fucking stupid.