I think ELO decay is defeating the purpose, that you said ELO does on this platform:
Another problem: When everyone starts at 0 ELO, you needed ways to feed points into the system. That's so far achieved by favorable K-factor for new players and the down-cap at 100. This way seemed quite balanced as it ensured that new players joining the community don't draw their points out of the community, dragging everyone down. So far so good - without ELO-decay. This system didn't need a mechanic to erase points from the system repeatedly and I think this is bound to drag everyone down - not just the players it's supposed to hit. People will hate to play with players whose ELO got artificially deflated.
I do realize that - as many other players - I've just jumped right at the change that I think is bad. So I'll also say this: I really appreciate most of the other changes you made - especially fixing the evaluation within teams!
But decaying ELO is really against this idea of what ELO shows. It's also blurring the difference to the Arena-Ranking - which is already a ranking for recent events. The normal ELO doesn't need to depend on any recent events - it only needs to show skill level.
Another problem: When everyone starts at 0 ELO, you needed ways to feed points into the system. That's so far achieved by favorable K-factor for new players and the down-cap at 100. This way seemed quite balanced as it ensured that new players joining the community don't draw their points out of the community, dragging everyone down. So far so good - without ELO-decay. This system didn't need a mechanic to erase points from the system repeatedly and I think this is bound to drag everyone down - not just the players it's supposed to hit. People will hate to play with players whose ELO got artificially deflated.
I do realize that - as many other players - I've just jumped right at the change that I think is bad. So I'll also say this: I really appreciate most of the other changes you made - especially fixing the evaluation within teams!