So excited/pleased that Riot is making keystones more impactful
I always disliked the gameplay boards rhetoric that keystones gave "too much unnecessary power", or that "there's only one good keystone for every champion." So much of the fun part of this game is weighing the pros and cons of keystone choices for your champion - take Kayle, for example. She can proc Thunderlords easily with an E and a Q, she can chase people down with Stormraiders, and her sustained DPS is great with Fervor. All 3 are great on Kayle, and all 3 have very different consequences on the way you'd play her.
In the upcoming runes and masteries overhaul, keystones are going to be even MORE powerful than before. They showed one that, after a few seconds of being in combat, gave 60% attackspeed and increased the attack speed cap. There's a support one that pretty much gives Lulu E to anyone who takes it (as in, an active from runes/masteries). I really can't wait to see what the rest of them are so I can get to theorycrafting.