Ryze, The Rouge Mage: Rework Concept

So me and my friends were thinking, and with ryze being the next one up on the chopping block we came up with, what i think. Is a really cool idea for his rework and i'd like to share it with you guys.

First and foremost, ryze is a master mage and he carries a book with him, how could a giant book only have 4 spells in it?

Possible Passive or R: Book of The Arcane/True Arcane Mastery

Ryze may cast this ability before activating his other ability's, if he presses and holds on 1 ability then presses another it makes a different spell.

If this were a passive it would do the exact same thing but he wouldn't have to activate something to use it and he would have 4 spells with different combination instead of just 3, in addition you could put a Cooldown on it that wouldn't be affected by his CDR and instead his level making it much more fair.

So let's say his Q was a line skillshot, he uses his R and presses Q then holds it and presses W, creating a spell that's completely different from their base spells with more damage or an added effect.

To make this ability not OP his base spells would be fairly weak and he would have no choice but to learn the button combinations making ryze extremely difficult but also maintaining his "Button mashing" play style of having to do very specific combos like a wizard, which was part of what makes him fun to play, in addition the enemy wouldn't feel like they are just being locked down by him because if he did have a stun it would be a button combo to do it and it wouldn't have 0 cooldown anymore making him more of a sustained mage instead of burst one.

Lastly to add to his difficulty if this ability were to be implemented his Cooldowns would have to have something happen, so let's say that it puts both spells on cooldown and gives them an extra 2 seconds of Cooldown that isn't affected by CDR, something like that so that he can't spam spells as much but would still be able to cast them fairly frequently.