On the Vel'koz update

My largest issue with Vel'koz is how his passive does not tie into his character or lore at all. His character is based around decision making, precise calculations, and geometry. A 3 hit passive doesn't seem to fit with his character design. I feel that for his rework his passive should be the focus. The new passive should focus on his quest for obtaining knowledge through dissection and disintegration. Since he's also what I would consider an APC (reliable damage, huge AoE burst, good late game due to his true damage) he could get away with a scaling passive like Cassiopeia has.

Instead of hitting champions with poison like Cassiopeia his passive should be based on killing minions, champions, monsters, and epic monsters. A minion kill gives 1 stack, a monster kill gives 5 stacks, a champion kill/assist gives 25 stacks, an epic monster kill/assist gives 50 stacks.

• 50 stacks Vel'koz now deals 5% of his damage on both his AA's and Spells as true damage.
• 125 stacks Vel'koz's Plasma Fission steals 20% of the champions movementspeed and gives it to Vel'koz (If a target has 340 MS they'll have 102 after his slow and Vel'koz will have 408 MS (if he has no MS items) for 1.5s)
• 250 stacks Vel'koz now deals an additional 5% of his damage on both his AA's and Spells as true damage. (Total of 10%)
• 400 stacks Vel'koz can store a 3rd charge of void rift.
• 575 stacks Vel'koz now deals an additional 10% of his damage on both his AA's and Spells as true damage. (Total of 20%)

What do you guys think? The effects of the stacks might be OP, but I think a stacking system like this would make much more sense with his character.

His current passive at level 18 deals (3 times his passive will be dealt if you combo correctly) 615 dmg. At around 600 AP his full combo at 575 stacks will deal 748 dmg additional true damage.

Edit: Changed some numbers after doing some calculations.

To put these numbers in perspective in a 30 minute game Vel'koz tends to hit ~10 kills+assists, 220 CS, a few dragons/barons, and sometimes a few blue buffs. This means Vel'koz hits 250 from kills, 220 from CS, 15 from blue buffs, and 150 (3 dragons) from epic monsters. This means he'll hit 635 stacks by the 30 minute mark (aka usually the end of a game).