The Ability to Change Runes/Masteries In-Game

I think it would be great if Riot implemented the ability to change your Runes and Masteries in-game.

On average, 2 or 3 games out of 100 I play, I spawn on to the Rift to find out that I've selected the wrong Runes and/or Masteries for my role/Champ.

This is not so bad when It happens to me in Normal queue, or when the champion I selected would slightly benefit from my choices, but in Ranked Draft it can be quite debilitating to my overall performance, especially where my selection does not benefit the champion at all e.g.** Full AP or Super Tank .**

I believe there is a need for this, I don't think I'm alone here and I'm willing to bet a lot of players out there have experienced a similar situation to what I described above.

To make this Balanced™ and "Fair" there would obviously have to be restrictions like :

Runes and Masteries can be changed before leaving the fountain for the first time in that game. After leaving the fountain changes are considered permanent for the remainder of that game.

Writing this also gave me the idea where one could change their summoner spells in-game with the same restrictions above. First Jungle clear is nearly impossible when you forget .

I'm probably not the first to bring up this Idea but I feel like the league community would be grateful if a feature like this was added to the game.