I will change it so the edit is at the top because people still somehow miss it: I am talking about the runes and masteries system itself, not including the fact they used to cost Blue essence to purchase as all that did was give an advantage to the old players of League and restrict the new players.
[Link to the next few quotes.](https://na.leagueoflegends.com/en/news/game-updates/features/coming-preseason-runes-reforged)
**"Runes and Masteries have problems. These systems are complicated, hard to balance, and don't give you enough room to customize your playstyle or adapt to the situation in champ select." (1)**
I don't want to make this post a 20 minute read, so I'll just say that they were not complicated, gave you room to customize your playstyle, and let you adapt to the situation in champ select. Maybe they are referring to how you couldn't edit your runes directly, but I don't see why they couldn't have just added this in, as the runes are not very complicated.
I can see how balancing the runes might have been tricky, because of how hard it would have been to tell if they were too strong or not, but this was 6 years ago and today they have ways to tell. Now you can see everything in the post-game, from how much your demolish did to how much healing you gained from taste of blood.
**"Forging a better Runes system first means concentrating the system's power into fewer choices so that each selection matters more." (5)**
They put this in the dev blog that presumably hundreds of thousands of people read and thought nothing of it. Removing player diversity and creativity was one of their major intents, directly contradicting their statement above about the old system not giving enough room to customize your playstyle. I don't understand why champions like Fiddlesticks and Ryze should be weaker just because they don't have a specific keystone that fits their kit. The Runes and Masteries were made to have little impact on the game, to only support your playstyle and not to define it. If you weren't playing at the time, click below and it will take you to the wiki where you can see all the old runes and masteries and what they did.
**"With this in mind we're moving those “required” stats into the background so you can focus on the parts that matter." (12)**
They moved all of the stats from runes they thought were "required" and put it directly into the champions base stats. [Patch 7.22 link directly to where you can click **every champion in the game** and see exactly how much they added directly into their base stats.](https://na.leagueoflegends.com/en/news/game-updates/patch/patch-722-notes#patch-champions)
12 of the 16 keystones in the game are literally just more damage: Attack 3 times and deal more damage, when you hit an enemy deal more damage, you get the point. (I know there are 17, but I am not counting Omnistone)
The 4 non damage keystones are Glacial, Guardian, Phase Rush, and Fleet footwork.
I don't believe the Runes and Masteries were perfect and could probably use some small updates and balancing, but I believe it was a much better system than what we have now.
TL;DR: Runes Reforged was added to remove options that let you customize and play how you wanted, while at the same time making those fewer options much stronger. The old Runes+Masteries system had a much smaller impact and were just small stats and bonuses that you could use to create cool and interesting ways to play, either making cool new strats or simply just giving you a sandbox to play and have fun in.