Ekko vs Vel'koz

Alright, let's take a look at these. I haven't played Ekko and I refuse to purchase him until he's balanced because I have morals, so I'm going to go off of assumptions based on the wiki entries. Please feel free to correct me if I'm wrong on any of this. So according to the wiki these two have similar passives, except one is exceptionally better than the other. The better one being Ekko's. Yes, Vel'koz deals True Damage, but as a Vel'koz main I generally stack magic penetration anyway for him so it really wouldn't make much of a difference.

Let's compare.

Z-Drive Resonance ON-TARGET COOLDOWN: 3

Ekko's damaging abilities and basic attacks build up Resonance stacks on his enemies, lasting up to 4 seconds. At 3 stacks the target takes 「 15 + (12 × Ekko's level) 」(+ 70% AP) bonus magic damage and is Slow icon slowed by 40 / 50 / 60 / 70 / 80% for 2 / 2.5 / 3 seconds. Z-Drive Resonance's bonus damage will apply spell effects. Z-Drive Resonance cannot affect the same target more than once every few seconds. Against champions, Ekko also gains bonus movement speed equal in strength and duration to the Slow icon slow .

VS

Organic Deconstruction ON-TARGET COOLDOWN: 0.5 Organic Deconstruction Each of Vel'Koz's damaging abilities apply a stack of Organic Deconstruction to enemy units for 7 seconds, up to a maximum of 3 stacks. Upon reaching 3 stacks, they will detonate, dealing「 25 + (10 × Vel'Koz's level) 」true damage to the enemy unit. Basic attacks will refresh the duration of the Organic Deconstruction Deconstruction stacks, but will not add additional stacks.

I'm assuming that the On-Target cooldown for Ekko is how often the final result can trigger, not how quickly it can add stacks. When you compare this to Vel'koz, he can trigger his twice within that time. Let's assume he lands his Q, both Es and his W and does. We'll go with level 6 or so with 120 AP for Ekko. Now, with these in mind, at level 6.

15+(126)+(87)=171 damage for Ekko with his passive every 3 seconds. Vel'koz is 15+(106)*2=170 damage every 3 seconds( the *2 is from triggering every 1.5 seconds, twice), if he pulls off his full combo. This does not include auto attacks, as unlike Ekko, auto attacks trigger his. So Vel'koz requires a lot more skill to trigger this.

Now, let's take the end-game example here. We'll stick Ekko fully built with 750 AP, which is pretty common for an AP carry.

15+(1218)+525=756 damage, plus an 80% 3 second slow for Ekko. Vel'koz gets a mighty 25+(1018)*2=410 true damage every 3 seconds, again, if he pulls off his full combo, or his ult. sticks the entire time.

Let's also note in Vel'koz's entire kit, he has a total of two slows, both of which are skill shots, one is channeled, as well as one knock up, which is also a skill shot. As for Ekko, he has one slow in his passive, another in his Q, yet another one in his W as well as a stun and a shield, and a dash AND a blink in his W (which can go through walls) and a teleport in his ult.

So, comparing two champions, even though they have different "roles", they're both AP and they're both carries. Why is one so much more powerful than the other? And if you guys want an explanation of the rest of their kits. I have that ready as well.