Able to change rune page and mastery in game?

So apparently, players would sometimes forget to change their rune page and mastery which will have a pretty big effect on gameplay. So I was thinking, what if we are able to change our rune page and mastery in game before the minion spawn. That would be nice, isn't it? Especially in rank games, you wouldn't want to play an AP champion with AD runes and mastery, isn't it? I really hope Riot can consist of using my ideas!