I consider myself an archetypal leaguer.
I have Mastery 7 on my fave champs. Nami. Cass. Yorick. Working on a couple of others.
And, I want a bigger mountain to climb. There are moments I feel like I am above and beyond Mastery 7 with Cass and Yorick. The majority of my wins are S to S+. I often get As on my losses, with stinkers sloping down into B territory. Sometimes I lose with an S.
How can has a mastery 8? Better grammer? Spelling improve?
Smiley face based on the number 8?
Let's talk some, my peers, and discuss what really makes a player a MASTER of a champion.
I have found one of the hallmarks between an average player, and an amazing one, is simple game count. You get up around 50 games, you'll have the basic mechanics and spacing down, you'll have your skill timing decent and you'll have some nuance worked out. You should have at least one central build plan down pat, with variations for when things get bad. And right around here, around game 50, is when most Champions ding the Mastery 7 mark if you are buying Mastery as soon as they show up.
Maybe in much higher level play it takes fewer games, but my point is, I bet most players can get a Mastery 7 in 50 games, if they focus on improvement with the champ and they keep an open mind.
But I don't feel this really repesents the limit of "Mastery". So you had 5 good games. That's just fantastic, buddy. I have logged HUNDREDS of games on Nami. I know full well that as you get past 100, 200, 500 games, you start to notice little things about a champion that you didn't know before.
50 games: Nami can go all-AP, but she's squishy. Fortunately, she can just stay on the back line and throw spells. She doesn't have to wade in at all. (Mastery 7)
100 games: Nami has a major move speed advantage against certain comps. All of her skills either speed up allies, slow down enemies, or apply CC. She's a great position controller. Building to emphasize this can be powerful. But dashes and blinks can dismantle this plan, and a small handful of champs can outrace her.
200 games: All of Nami's skills deal damage. If, by some chance, she gets fed, she can be impressively strong and safe at 1v1. Enemies can underestimate her, and building around an early lead for a mix of AP and health can make the matchup unwinnable for all but the most stubborn enemies.
300 games: Nami's biggest problem stems from the fact that her skills don't inflict enough total damage for the mana cost to be lethal, given the limit of her mana pool. And the easiest fix for this, is to enlarge Nami's mana pool somehow. Tear of the Goddess, Lost Chapter, and Ancient Coin all help to fix this problem. Other recent solutions include Biscuits, Manaflow Band, and Presence of Mind. Nami's most powerful starting item may in fact be a Sapphire Crystal.
500 games: Nami has a glitch in her ultimate skill. The glitch causes the wave to launch exactly backwards from where you aim it. It triggers less than 1% of the time, but when it happens, you're going to look like a complete idiot.
These kinds of insights only come with lots, and lots, of games under your belt.