I have a concern with the suggested Vel'Koz changes.
Riot stated that what they wanted was for Vel to find a more distinctive role as a poke champ. One paper, this sounds fine. But it results in an identity issue.
Vel'Koz is supposed to melt people. Why? Because that is literally how he was advertised, written, described, everything. While Riot could argue for Morde's rework that he was not technically called upon to be a one-shot chop shop when he was released and that he kind of just ended up like that, you can't do the same for Vel'Koz in the slightest.
What's his trailer? Lasers. What's his lore? More lasers. What's his signature move? Mother fucking death laser. What's his own pick quote? "Knowledge through disintegration."
What you are suggesting as a more "distinct" role for Vel'Koz is directly counter-intuitive to his entire identity - and I mean his entire identity. You've focused so much on his Q being a signature thing and the "geometry" identifying him that you forgot that literally everything else does not support that.
So what does make sense for Vel then? What would his lore lend you to think about him? I have played Vel quite a bit, I enjoyed him, but his abilities are very much wonky and wobbly and easy to dodge, lending themselves to basically only being truly usable in a teamfight when the shots are flying left and right and nobody's fully focused on avoiding that stray E/W/Q. But there was one thing I always trusted Vel to be able to do - tankbust.
Well why can't that be his mage identity? Who else is a tank-busting AP mage? The answer is you don't have one - you have Vlad and Swain who basically do heavy sustained damage to everyone constantly. But you don't have a true, immobile powerhouse that focuses on disintegrating the front-line. I suppose Anivia fits that a little bit, but even her playstyle leans itself more towards being an anti-siege and area-control mage. I wouldn't point to her and say, "That's her. That's the designated tank buster." The truth just is you don't have a specific mage to turn to to focus on killing tanks - you have poke champs like Nidalee and you have sustained damage mages like Swain. But you never ever say that's their job. No, Nid's job is even to spear squishies and maybe poke tanks as a byproduct, and Swain's job is to march in and be terrifying while dumping his damage out on the enemy ADC to force them out of the fight. It's always prioritizing the squishies.
So that's my argument - don't turn Vel'Koz into another poke champ. You have quite a bit of poke champs. No, have him do what he says he will - obtain the knowledge he seeks through disintegrating the fuck out of people, whether they're bulky or not.