Ideas For a Kassadin Rework/Buff
Just recently I have bought Kassadin thinking he would be a very interesting and fun champion to play as. After the first three games I loved him. He matches my play style in almost every way. But then I remember the Kassadin "rework" and the nerfs to his ultimate and how he has the lowest win rate in the game (besides Tahm Kench). People keep telling me that he is a bad champion and has fallen out of the meta. However, I ignore most of their criticism, but it makes me urge for changes to make Kassadin "viable" again and to give him more love since he only has a 1.5 play rate now. So, here are my thoughts and ideas for future changes that I hope Riot can implement (obviously they don't have to) to help out The Void Walker 
Q (Null Sphere): I think Riot should slightly buff the Q base damage like they did with Ryze a while ago and/or higher the ap ratios for more burst to come in the same position with other ap bursters. They should also increase the magic shield duration and the amount of magic damage it blocks. Maybe they should even add in a slow or some small amount of cc but obviously not too much. If this is too much or if it's not enough they should lower the mana cost and/or the cooldown.
W (Nether Blade): Honestly, I think this ability is fine, but maybe higher the early game base damage a little for easier csing. Even though this might sound OP, they should add in an additional effect/passive similar to Pantheon's Hearseeker Strike.
E (Force Pulse): When I use this ability it just feels overwhelming even with a lot of ap. They should slightly higher the ap ratio or the late game base damage. I also think they should change this into a cooldown ability instead of a "stacking" ability. The cooldown should be a maximum of 5-11 seconds since sometimes it takes a while to get the 6 stacks for this ability and sometimes (usually during late game) it takes very little time to get the 6 stacks for this ability. Lowering the high mana cost it has could be helpful.
R (Rift Walk): This is the ability Riot has the most trouble with balancing on Kassadin. I heard some people calling it the "Rift hop" because of its low range. I suggest highering the range by 50 but not too much because the range of riftwalk on the old Kassadin in my opinion was overpowered. I also suggest making the ability also scale with ap and not just mana or maybe even just ap because I never see anyone buying an Archangel's Staff, just a Rod of Ages which from the new ap items rework the Rod has been given less mana (but more "stacking" mana) which makes him quite weak early game.
These are my ideas for buffing and reworking Kassadin. Again, Riot doesn't have to take them. All I want is to make this fun champion viable again without him getting a high ban rate and being overpowered like before. Yes, he is good Diamond and up so maybe give Kassadin a series of small buffs. After all if Elise was buffed shouldn't they buff Kassadin, too?