Let's talk Kassadin for a moment

Unless there's somebody out there, playing League but living under a rock, then everyone knows the story of the rise and fall of Kassadin. It is quite clear that his previous strength used to be his mobility, primarily given to him by Riftwalk. But by reducing the range of his ultimate, he can't do his job as an assassin, which is to get into the backline and assassinate key targets.

I would like to propose a possible solution. It's clear that having too much range on Riftwalk is too overbearing (remember S1?). On the other hand, having the range too low kills any possible chance of Kassadin being a viable champion.

I propose that Kassadin's ultimate should scale up range with consecutive uses (along with the mana costs). Starting short, Kass would be able to Riftwalk a short distance for a short mana, while his next Riftwalk within a short time would let him jump a larger distance for a higher cost. He should then be able to have the ability necessary to do his job without being too overbearing. If something is needed to balance out this possible buff, I would also propose to have the cooldown scale up with consecutive uses. That way, Kassadin will not be able to hop in, blow someone up, then hop out since longer distances would necessitate longer cooldowns; he will have to choose his strikes carefully.

If we consider that Riftwalk functions in a similar way to Flash, then the mechanic wouldn't be too different either. The longer the distance Kassadin wants to jump, the more mana it will cost and the longer he'll have to wait for his next jump.

Please take a look at my proposal and upvote if you think this is a good idea. I would like to see Riot find a way to make Kassadin a viable champion without being too broken.