I don't like the new Runes.
I'd be willing the bet the new runes lose a massive amount of efficiency compared to the old ones.
You know how you can solo Dragon on every character level 1? It takes incredibly specific runes per champion to achieve that, and I'd be willing to bet that is lost.
The old runes were honestly really good. All Riot needed to do was let you edit them in champ select.
Things that are incredibly niche are going to be lost from this, the days of 'tweaking a character' are over as massive customization is replaced by CookieCutter strategy. There will no longer be a dynamic to taking Movement Runes on Katarina, verses AP or AD or MPen. There will simply be a solely optimal build and anyone that doesn't run it is 'stupid'. That's what makes me sad about this update.