i played the nerfed kassadin
not a real kassa player here but i can just share my feelings
i played him in normal ofc his ult range might be lower but its actualy funnier for me to riftstep or even riftstop as rioter said instead of rifting across the map like a freaking kalista on steroids
with 40% cdr his ult has 1.8 seconds cr and when stacked dealt good damage
for me he only needs some tweaks, but his playstyle feels kinda funnier to me (i never realy enjoyed the guy), to hop around short distances
also some notes his ult is important for wave clear, but his w makes it impossible to use it that way (mana) his w could use some range augnenting since he isnt the best runner and his slow is short (might not catch a person after r+e combo, so his w might get useless) you can build insane mana and he still goes oom after only a couple of jumps q range feels insanely long compared to his other skills, you could aim some changes at mmaking it fit him better (also the viauals, they usualy involve splashes of void energy, ball doesnt fit here)
final conclusion of mine, its still kassa, less annoying, but now his past nerfs realy show themselves