After 5 days of not dueling a worthy opponent, your rating begins to deteriorate. It should probably happen after a month, not a mere 5 days. I'm sure a lot of people I regularly duel against enjoy fighting me or one of my alts when it has 100~ rating and they lose 20 every duel. Surely that's not why some people just refuse to duel me. The deterioration serves no real purpose, it should either be removed, or delayed significantly. This will boost the average elo rating, as well as properly creating skill classes like other elo systems.