Kassadin fills the role of an extremely mobile mage with high burst capabilities. Because of how his kit works, he’s always been difficult to balance. The primary reasons for his high level bans are the innate lack of “outplay” potential by an opponent and the complete ability to control when and where engages happen due to his hyper mobility.
Kassadin’s primary identity is hyper mobility, with a secondary identity of assassin and tertiary identity of anti-mage. Any attempt to alter the champion would need to open up a player’s ability to counter the moves that a Kassadin makes. This should be done by increasing the ability to survive his onslaught of damage (as in return more damage than you take when he engages on you), reducing his chasing potential (less control over engages) or locking him down when he engages (counter acting his mobility).
Kassadin’s strengths are his high mobility and high damage. His weaknesses are lower-ish utility, mana costs and melee range. High mana costs and melee range hinder his strength in laning phase, which has been the primary tool used to introduce weakness into his kit.
With all of this in mind, I have three proposals to alter Kassadin’s kit.
1) Remove/severely reduce the power of the slow on his E. The slow doesn’t add to his identity, as he is mobile and an assassin without it. It allows an opponent to have a little more control over an engage. It keeps his laning phase weak, while also reducing his utility. Overall, it would remove some power in his kit without damaging his identity. Two issues may arise from this change – one, that he still doesn’t have the necessary “outplay” potential for an opponent, even with the slow removed, and two, his E might feel worthless for a player using it. These are both issues on which it would be important to keep tabs.
2) Make him more susceptible to slows after he gains his ultimate. Using a slow on Kassadin, for instance, would be twice as effective. This would hurt his identity to a degree (namely damaging his mobility), but the stronger slows do not hurt his ability to dash around with his ultimate as usual. This would introduce a weakness into his kit that opponents would be able to actively use against him. As slows are a pretty common form of CC (and can even be purchased), there would always be an option to counter act Kassadin’s dashing mobility by limiting his walking mobility. It would be an extremely unique weakness, but one that would introduce a little more skillful play into the equation. One possible issue includes frustrating Kassadin players once they gain their ult – they have to make a trade off with their walking mobility for dashing mobility. While it’s strictly better to have dashing mobility, it still sucks to have to lose something to gain something else (although he only loses something when slowed). It also might not really make a difference – slows aren’t going to hurt his ability to dash on top of a champion.
3) Reduce his base move speed to the minimum. It would hurt his laning phase, hitting one of his weaknesses. It would also not hurt his strengths or identity all that much. The issue, however, is that it doesn’t really target his issues in competitive play, other than just making him weaker. He’s still just as unhealthy as ever.
Update: So I watched a little LCS this past week and kept tabs on games with Kassadins in them. Every time one of my changes would have altered a play, I tried to store it to see how effective it may have been. Generally speaking each of the changes would have achieved some of the goals, but even with them Kassadin’s identity would still have been the same. There was one fight where he dropped all his burst on a player and they blew up, where his E slow didn’t really matter. However, there was a later fight where Kass’s team mates were able to catch up to an enemy because of the slow – that would have changed things a little. This was pretty common throughout the game. I also took special note of Zionspartan’s build on Gnar with the Frozen Mallet – I think that could have been extremely effective against a Kassadin with the second change. Overall the big thing I noticed was how weak his laning phase was and, if he couldn’t get kick started after laning phase, he would be pretty much dead weight (feast or famine). That’s an issue that definitely needs some work, but it’s more indicative of assassins than just Kassadin. It’s just another issue he has. Targeting his laning phase would only make this issue even more prevalent, so although it’s a weakness it’s not really one that’s good to target.