Ekko does too much damage for a utlity carry
Compare Orianna And Ekko. or Ekko and Ahri What you will find is that Ekko does too much damage and has so much utlity that he makes Orianna obsolete and excedes the OPness of Ahri. The only way to fix this and give ppl a reason to choose Orianna, Lux, or other mages, is to Nerf Ekko's damage.
Ekko's passive does way too much damage compared to Orianna's passive. It needs to be changed to 15 + (6× Ekko's level) (+40% of ability power)
Ekko's Q does much more damage and has a Slow on it making it rival or exceed Ahri's Q in damage and utlity. The damage on this move needs to be reduced.
For the utility in Chronobreak it needs to have it's damage reduced to 150/225/300 (+80% ap)
His W Has a passive on it that needs to be removed. A Utility Carry does not need to do about 7% hp damage and 250 damage from Timewinder on a basic attack to someone with 30% hp left.
At level 10 Lucian has 1174 hp , So if Ekko is at lvl 9 has 90ad, 150 ap, Lichbane, and is at 700 range Ekko will 100 - 0 Lucian with his Q+E+AA combo alone and there is nothing Lucian can do about it.