Thoughts for Mastery level 8, 9 and 10.. or more..
My thoughts on the goals and rewards.
Mastery 8 goals = 3 S+ tokens & 82,200 mastery points. Mastery 8 icon/emote. Mastery 9 goals = 5 S+ tokens & 120,000 mastery points. Master 9 icon/emote with loading screen banner while wearing icon on specific champion. Mastery 10 goals = 10 S+ tokens & 167,400 mastery points. Master 10 icon/emote with loading screen banner while wearing icon on specific champion, Name tag shiner/color/highlight modifier in and out of game and can colorize your banner.
Mastery Legendary = 25 S+ tokens in ranked queue with specific champion, 250,000 mastery points (Can no longer be earned in normal, points will only accumulate in ranked queue) and 50+ ranked wins with specific champion and must be in good standing with honor/behavior level. Must also have at least 1 champ on mastery 10 from each role (Assassin, Fighter, Mage, Marksman, Support and Tank).
Reward = Exclusive rare champion skin/s of your choice or RP(20,000) if not available for desired champion: example unmasked Kayle, Pax Sivir, Masquerade Evelynn etc. etc.... A high honor and congratulations letter from Riot. Every thing else mentioned above in mastery 8, 9 and 10.. Exclusive extra honor level, level 6, level 7+ and so on for each new honor level league releases, you will be able to go a step higher than normal players with this exclusive permission for a new and even better flare on loading screen banner.
And ultimately, to be recognizes as being one of the greatest players on League of Legends.