Ryze's Choices Will Lead to Disaster
According to the Map of Runeterra, Ryze stores his collected runes in northern Demacia. While I understand he needs the Petricite to contain their latent power, you should not hide weapons of mass destruction in a country in a state of constant war. What if a Demacian finds them? Do you really think that a fear of magic will be enough to keep them from taking them? Ryze isn't there to guard it. No one is since he can't trust anyone else to interact with them longer than a moment. What if a Noxian spy finds the vault (or Noxus turns the tide of battle and comes across it)? Do you really think an empire that puts power above all else would hesitate, even for a moment, to use the world runes?