Or you know, they could remove 2 of his "utility" things in his kit.
Ekko has:
speed from passive
slow from passive
slow from Q
slow from W
shield from W
stun from W
dash that doesn't require target from E, blink from E ( do note, I've put these both in the same place)
more mobility on R
Heal on R
Total of 9 utility stuff in his kit in addition to his damage (and %hp damage, coz why not).
Now compare this with actual utility champions like Morgana
spellvamp from passive
root from Q
shield vs magic damage from E
anti cc shield from E
Slow from R
Stun from R
Total of 6 utility things in an utility mage kit.
Even Janna.
Movement speed to allies from passive
Knock up on Q
Slow on W
Movement speed on W
Shield on E
Extra AD on E
Knockback from R
Heal from R
8 utility things on a pure utility champion.
Or Leona:
extra magic damage from passive
stun on Q
MR and Armor buff on W
Snare on E
Gap closer on E
Stun on R
Slow on R
7 utility stuff on a tank support
Ekko's kit is just overloaded. Not just for an assassin, but for any class. Tanks, Mages even Supports have less utility than Ekko in their kits.