As a former Ryze main,
New Ryze makes me cringe. Hard.
I was under the impression that this was going to be a nerf to his ez mode "click and win" gameplay but an overall buff if you're good with the champion..sorely mistaken. Ryze is in a far worse place than prior to the nerf, and IMHO ya'll fucked up when you messed with his ratios. Now he has both subpar AP ratios AND almost unnoticable mana ratios.
I get the concept of "windows of opportunity" and I generally agree with that philosophy, it was just very poorly executed with this change. After building tear and a Catalyst, I was awarded with about 45 extra damage. I also decided to run mana regen in my masteries given the nerf to his regen rate, and even around level 14-15 it would cost me about half my mana before I could pop my passive and actually be able to trade effectively. And the "5" number seems a bit random. Generally, in teamfights, by the time I had my passive up all my skills were on cooldown and I ended up getting maybe 2 spells off before it wore.
You can do better riot. Stop half assing things like these. IF you're gonna rework a champ, REWORK him. This is weaksauce and in current state, wipes Ryze out of consideration as a viable caster.
Highlight of the update for the champion was the changes to his missile speed. Looks nice.