Ryze is in a somewhat terrible state right now. In competitive he is semi-viable with seeing some picks here and there. However, in soloq, exspecially below masters/challenger his winrate is absolutely awful.
As you can see he hovered around a 41% winrate during the past months and currently has the second lowest (right after Kayne) winrate even though he is seeing a slight increse in winrate right now.
In my opinion (feel free to correct me in the comments) Ryze's balance problems come from the fact that when he is viable in soloq he is busted in competitive play. If he is balanced in competitive play he is terrible in soloq.
The biggest offender to this is his ult. While nearly completely useless in low elo as your team won't respond to it and only somewhat useful for other shenanigans in platin it is not very useful in soloq. Meanwhile in competitive and (really) high elo it is very strong as it allows for the repositioning of multiple teammembers or cutting of escape paths and other things as your team will most likely be capable of understanding your plan by using your ult. In competitive it is even easier as you allways have 5 people communicating via voicechat the whole time.
Currently Ryze can skill his Q 6 times and his W and E 5 times. A possible solution would be to give him the udyr treatment. Make him able to skill his W and E a sixth time if he wants to do so. Skilling E a sixth time will give him his 100% dmg buff on Q again (like pre nerfs) and W will snare for 1 second again (like prenerf). You could also further adjust their CD's to make it viable to miss out on your ult. (Don't quote me on these numbers as Riot would have to test which numbers work and which numbers don't work.
Now the Ryze player can chose to either improve his fighting or chose his old ult if he thinks it is useful and his team is able to use it accordingly.
Pro players will still be able to provide the repositioning of the current ult while in soloq players can choose to not skill their ult if they think their team is not capable of putting it to good use.
In my opinion this would fix Ryze's balancing issues and a test on the PBE might be worth it.
TLDR: Give Ryze the Udyr treatment and make him able to skill W and E a 6th time instead of ult. This would make his ult which is currently only put to good use in competitive not a balancing nightmare. Ryze players who like the current ult will still be able to use it. Noone really loses anything.
Edit: Or make him able to choose between 2 different ults when he reaches level 6.