Mastery Decay
I was considering what exactly the Mastery levels of champions truly mean for every individual, and I managed to reach a conclusion: we do not really know. The fact of the matter is that someone could have reached level 5 mastery on a champion and stopped playing him or her months ago; on the other hand, that individual could have been spamming that champion for a whole month and got it only recently. Or that summoner has been playing that champion for years. Sure, the amount of points can determine how much that champion was played, but we do not know how recently.
We really do not know.
I believe that a similar effect should be granted to Mastery levels as is for ranked. A Mastery Decay would set in for any champion you had not played for a month, with the decay being higher the higher level that Mastery is. For example, level 1 and 2 Masteries -- just like Bronze, Silver, and Gold ranked Ladders -- will not result in any sort of decay. Level 3 will result in a slight decay. Level 4 will be higher. Level 5 will be the highest decay.
I understand there are a lot of champions, and some of us can pride ourselves at reaching level 5 mastery in dozens of champions, if not most of them. I thought that a month before decay hits would allow enough of those champions that you can truly play masterfully to stay their levels, while others start to decrease.
Comments? Opinions? Complaints? I thought this might be an interesting idea.