We need more or better Keystones.
When Keystones were initially introduced last year, I was extremely excited to see what they would do for the game. I saw potential in that champions would change or adapt their keystones depending on their and the enemy's teamcomps. This did not happen however because for most champions, there was only one clear cut "best" option.
Take Syndra for example. If she wants to go down the Ferocity tree (which gives the impression of offense), she's already restricted from 2 of the 3 keystones. The 3rd keystone, Deathfire touch, has a very weak AP scaling and is also tuned towards DoT champions. So then she goes to the next tree, Cunning, and immediately Windspeakers is out of the question. If she were to consider Resolve, there would be nothing there either as those are mainly geared towards tanks. So it's between Stormraiders and Thunderlords, although something like Stormraiders would be good for kiting, Thunderlords is just too easy to proc on her and tends to be the keystone of choice. Rylais also helps with kiting.
Several champions face this issue where they have to choose between 1 really good keystone and 1 weaker keystone.
Skarner suffers a similar issue, as although in the past a more offensive auto-atk oriented build would work (which could work with either Fervor, Collossus, or even Warlords), the complete tank playstyle only keyholes the Collossus keystone.
I understand these are case by case scenarios but I think it's very rare to find a champion who works with multiple keystones simultaneously - perhaps Jhin can run Warlords/Deathfires/Stormraiders/Thunderlords?
Theres some serious potential here, both thematically and functionally. Similar to how having multiple, yet balanced champions creates diversity, having multiple yet balanced keystones can function. Maybe 5 keystones per tree would allow for more diversity/choice. Something to think about.
Also I know this isn't the thread for it, but perhaps Lethality can be explained better in game (how it works). And also why is there AD lethality but no AP lethality?