idea for a more interesting version of Kassadin's E

Kassadin's E is pretty boring. In its current state, its basically a standard nuke with an extra gate on top of cooldown and mana. I was somewhat frustrated that when Riot decided to buff Kassadin, they did not look to get creative with how the E spellcast gating mechanic could be changed. This idea came from that.

This was mostly done as a fun theorycrafting kind of thing, just to show an example of the wasted potential that Kassadin's E spell gate presents. While I did run the numbers to see how this would fair in comparison to his current iteration and to come up with some placeholder values, the numbers I have are much more powerful than the current version of his E.

> E - Force Pulse > Mana Cost: 100/120/140/160/180 + 10% Maximum Mana > Cooldown: 10/9/8/7/6 > > Kassadin deals 50/75/100/125/150 ( + 45% AP ) magic damage in a cone in front of him, slowing enemies hit for 50% for 1 second. > > When nearby champions cast spells, Force Pulse's cooldown is reduced by 1 second. Enemy spellcasts also reduce Force Pulse's mana cost by 20%, and Force Pulse gains damage equal to the change in mana cost. > > (for reference, this is the percent of total mana cost that has been converted to damage after X stacks: 0/20/36/49/59/67/73/79/83/86/91) >

With a 800 AP, 3000 Mana build, this is hitting 860 damage at 6 stacks (the current requirement to simply cast the ability), whereas the current E is dealing 740 damage. The upper limit on the damage (infinite stacks) is 990 (330 + 45% AP + 10% Mana), while the lower limit (0 stacks) is 510 (150 + 45% AP)

Now, this isn't perfect by any means, but its just one way that the spell charge mechanic of his E could be a positive rather than simply a gate. The idea behind this is to reinforce Kassadin as an anti-mage by making his damage directly more powerful based on enemy spellcasts, and to add to Kassadin's unique interactions with mana as a resource. With few stacks, Force Pulse should still be "uncastable" by virtue of having a punishing mana cost, but when multiple enemies are around spamming spells, Kass will be pumping out high-value Force Pulses every second.

This really wouldn't work with his kit the way it currently is (I imagine he'd need a completely different Q for something like this to be healthy), but again, this is just one idea.