That's interesting
However, there's a mistake in second rune page's description - you cannot take second wind and bone plating together cause they are in the same row
But the idea is fun, I tried to play ap Gnar before and it was... not successful. Guess I need to try again

I use this build all the time, it's the best and most midlaners don't know what to do against it. I've also tried this once or twice botlane, and it works great as well, considering gnar is never played botlane, and adc mains don't know how he works as well as a top main.