Revert the Ryze nerf to his W? Or change it in general?

In my opinion, the nerf to Ryze W came completely out of no where. The ability is not overpowered in any stretch of the imagination, and now its almost useless. Ryze had 1 defense against assassins and riot took that away, and now there's the banshees veil that every ap mid buys.

I know that if rune prison is cast on an opponent affected by flux the duration increases to 2 seconds but its still just a root, and that being said, isn't even very good. I can name better abilities with a similar cooldown that DON'T require a previous condition to be met to cc someone for 2 (or more) seconds.

And with all these assassins running around Ryze only has his rune prison as a defense and that only slows them down for less than a second before they jump on him and kill him. It's even worse when that assassin is someone like , or , champions who put banshees veil in their build path 90% of the time. At which time you have to make a choice; give up completely and don't use any abilities; use rune prison on them and have it not do anything; use spell flux on them to remove their spell shield and then rune prison them for .75 seconds and take 2 steps before they jump on you; or use overload on them and risk missing it during one of their jumps, then use spell flux and rune prison to root them for 2 seconds but at the distance you can cast both spell flux and rune prison (due to their cast times) the assassin is already close enough to you that even when they are rooted in the middle of your team they can just pop one or two abilities and kill you.

Even if the rune prison base duration was increased to 1.25 seconds and 2.5 seconds (still less than Morgana Q and .25 seconds longer than fiddlesticks FEAR) when fluxed the ability would still not be overpowered do to the cooldown and the fact you can dodge Ryzes combo in lane by standing BEHIND minions (not inside the wave). Plus this would allow Ryze you actually kite champions again because at the moment the only real purpose the ability holds is in getting one half of a shield. Using it under tower is only useful half the time with almost every other champion either have longer range than Ryze or having a dash.