I've made a similar post several months ago and I'm making it again because it's something I strongly feel the game needs. Lvl 7 has become completely meaningless and nothing to brag about, I have multiple champions at lvl 7 that I don't even have 40k mastery points on and can't play for sh*t. It does nothing to show your dedication and/or experience on the champion.
There are people with millions of mastery points on their champion and with nothing to show for it. If you added one or two new mastery levels it would literally breathe new life into the game for me as I, and probably many other people, would have something (or at least one more thing) to work towards. But I'd even settle for a small alteration of the lvl 7 mastery emote based on the amount of mastery points. It has simply been way too long since the release of M6 and M7 and it's about time you give us the next step.