@Riot -- What are some foreseeable plans you have in mind for Champion Masteries?

I am a strong believer that many players in this community love self-expression and showing off (in a good way, of course.) This is done through summoner icons, skins, ranked borders and even champion masteries. I feel like the new addition of Mastery levels 6 and 7 are a great way for players to express their love and dedication to their favourite champions. With that said, do you intend on further expanding player expression through champion mastery, or is the most recent addition the end of the road?