Keystones: Failed experiment
The game has become 'which champs synergize best with the strongest keystones'
Also keystones didn't change the way anyone plays the game. Everyone does exactly the same as they did before but now get an extra effect on top of it. That is the problem. It didn't change anything. It is just another nuisance to balance around on.
1st: Tryndamere and Yasuo meta 2st: Brand and Anivia meta 3rd: Thunderlord meta 4th: What is next to come?
Meanwhile champs like Anivia, Swain and Malzahar got nerfed during the proces because their synergie with their keystone was too strong and their keystone got nerfed as well leaving them in a worse position prior to the implementation of said keystone. Same goes for Brand, Tryndamere and Yasuo in less extend. So each time we move on to 'the next best thing'