New keystone idea
Spell mastery
The first ability you level up in a game gains max CDR for the rest of the game.
This means at lvl 1 you get 40/45% CDR on one ability (non ultimate in most cases) at the start of the game. This is your keystone benifit, but it also devalues CDR builds a bit.
So for example a riven could take this ability for Q for low CD Q's but she might still want CDR to lower he other ability CDs.
This could have interesting implications on champions who are utility based like supports as well.
It is also a double edged sword for champions with resources as they can starve themselves much faster of energy / Mana.
This is just an idea I had and wanted to post it.