Idea to improve Kassadin

Hi

I have an idea how to fix the problem with Kassadin. Kassadin is in ca 100% of the games picked or banned, soloQ and LCS. I think his problem is the ultimate. And here comes my Idea:

Make him let his ultimate just use if a target is silenced. You dont have to change the abilities just some fine work. Change the Q cooldown to about 6 or 7 seconds and increase the range, but decrease the damage so that he dont became a strong lane bullie . His ultimate have a cooldown of ~3 Seconds but as i said its just useable while a target in a certain range (~1200 like Yasuo or sth like that), but increase the range he jump with a ult. So with my idea you for example silence the tank or a teammember silence someone in a front line and jump direclty to the backline to assassinate the enemy carry I think this will make him more playable and let some points open for counterplay. It will have a huge impact and dont change much on his kit, but his gameplay will change a lot. Furthermore this would change his beeing of an mobility-creep but take a bit of his assassin style away, but like yasuo without the right comb you cant get good into the backlines of your enemy. PS: Sorry if this Idea was posted before but this was in my head for a few days and i wanted to have some of your toughts and sorry for typos or the language, but im not native english.