So Riot, I noticed something missing from the new rune system...

While I was looking through the new rune system, I noticed there was a distinct lack of penetration runes. With magic pen marks being the most popular marks for ap carries and lethality runes being fairly popular on ad assasins (talons and zeds of the world), I find it strange that there wasn't a replacement runes for these pen runes. Was there some internal reasoning why a replacement wasn't made for pen runes or was it an oversight?

Overall though, I'm looking forward to seeing how these rune changes affect the game.