Below : Anectodal evidence from a bad player. Take with a grain of salt. And I have lots of salt.
I dunno, Ryze has been a consistent issue, balance wise, since the beginning of time - almost always having to do with the fact he scales with mana. There have been nerfs on a few previously tanky mana items (Frozen Heart, Banshee Veil), but he just seems to be impossible to punish once he comes back to lane with tear and catalyst. Unless you're playing somebody who can just simply outrange him like Lux or Xerath, he is one of the worst champs to have to play against because of his instant point-and-click CC. Basically, once he gets in range, you're going to lose 1/2 - 3/4ths of your HP instantly, regardless if you're behind minions or not.
Most other mages/mids simply can't even do anything to him because he just does his point-and-click snare and combos for insane damage.
They gave him skillshots on his Q, and quasi-skillshot on his E, but it doesn't really matter when he has a 2s root.
Seeing him gain a 1.5k+ shield instantly when he pops passive + Seraph's is so ungodly frustrating and makes him almost unkillable in teamfights, while having such insane damage on almost no cooldown.
He suffers from the same balance issue like Vlad and Kayle once did - double dipping survivability and power from passives that increase both substantially. With lots of mana, not only does he gain insane damage, but also tankiness - not only from the items themselves, but also from the passive shield he gets now.
Would it really be such an issue to take away the mana scaling on his abilities, and compensate with higher base dmg / AP ratios? He would still benefit from Tear/Seraph's because of his low cooldown spammable abilities, and his playstyle would be largely unchanged.
I'm guessing his inconsistent winrate is a result of his team-reliant ult. Most Ryze's I see just use the ult to transport themselves behind an enemy while the rest of the team flanks. It's rare I see people coordinate the ult to interrupt a baron/drag attempt, or to pincer an enemy between the team and a turret, though I imagine these were the intended uses.
