Ability power and ryze don't go together anymore. If you stack AP, prepare to lose every fight against anyone, because 3/4 of your skills are useless that way. The only thing SLIGHTLY useful with AP is spell flux, and that got a hard nerf to it. Ryze has been turned into mana and CD hog, who can gain lots of survivability from certain items. AP doesn't work anymore with revamped ryze, I know rabadon looks inviting, but it's not GOOD for him. Try using something like banshee's or frozen heart, to give CD and mana, in turn, damage. Rylai can also be exchanged for either of those to make him more effective. RoA is still good, and I would recommend ionian over sorcerers now, even if you eventually go over 40% with frozen heart it's still effective. Early tears are good, so I would skip dorans ring since you end up with nearly 3k hp and at elast 100 armor and MR with what works well now. Go straight to sapphy to get more powerful RP and overload. Prioritize spell flux last as well, only getting 1 level early to harass slightly.