Kassadin the fallen, the Void Walker with no power

Since we lost the old boards and a **14 **page thread there I'm going to bring it up here on the Gameplay & Balance boards. I would dearly love to get some Riot official response on this because as it stands almost any person that's played Kassadin lately just feels like they are purposely crippling their own team by picking him. I've gone over this a bunch of times with a lot of people so I'll try to tl;dr it but since it's trying to summarise the old thread it's still going to be long.

Basically in his current state he doesn't offer anything that other popular mid laners have and they can all do it a lot better. Yes, he has Rift Walk and it gives him mobility and yes I acknowledge he can still snowball but there are two major points to add to that. Rift Walk has a cooldown and the stacking nerf really hit him hard. It does little damage but I know it's still a powerful ability. However, the likes of LeBlanc, J4, Akali, Lee Sin, Zed, Talon and others can all dash in a fashion that's much more damaging than Kassadin with far higher burst. The snowballing potential is very low unless you have someone literally feeding him kills very early. Syndra, Orianna or Zed can still be useful if they're behind by offering utility, split-pushing or the threat of high burst with a whole team stun but if Kassadin doesn't snowball he is very ineffective.

"But his late game is scary!" Tell me any champion that isn't scary late game with a full build. It shouldn't be used as an excuse for a very crippled early AND mid game. Lee Sin's power is often excused with "but his late game sucks" which, frankly, isn't true. He may not have the ability to slaughter people that he has early but there is always the risk of him diving in, kicking your ADC away from safety and then safeguarding to get away. Even if it was true the difference is obvious. You always have an early game and mostly a mid game but you can play a lot of games and not reach late game meaning you picked a champion that has no effect on the outcome for the most part.

"We finally have 6 bans!" Fantastic, pleased for you. You can ban one of the many other lane bullies that just took his place or an ADC, a jungler, top laner, support. There are some that are just banned a lot in Kassadin's place so at best you've exchanged one perma-ban for another. Besides this isn't the Kassadin that was a nearly unstoppable killing machine that you can't escape from. I don't doubt that higher tier than I can use him a lot better and still be quite powerful but I just have to look at Worlds where he has been used a handful of times and only one game, where he got two very early kills and a few more after (cleanup kills) did he have a chance to snowball. The others he was very ineffective in general.

I and others don't want a return to the perma-banned unstoppable assassin of old but we would like a champion we enjoy playing to be at least viable and not feel like a burden for picking him over Syndra, Orianna etc. Rift Walk feels like it's as balanced as they can make it with the 20 second stack fall-off and the high mana cost but honestly I would be fine if they removed the damage from it in return for a few Quality of Life buffs to his Q and W.

If you're going to post please try to offer something constructive and if you've seen a really successful Kassadin player then by all means link to their builds. I'd love to be proven wrong but when the best of the best at Worlds don't generally pick or ban him and can't even use him unless fed hard early it tends to make me think that he isn't a viable pick.