Yeah, I'm not a huge fan of the Ryze changes tbh. To me it seems like the balance team sorta caved to popular opinion of him being OP, and tried to significantly rework how his playstyle irons out mechanically, without tweaking a few numbers first.

And this isn't going to be a popular opinion, but Ryze wasn't OP to begin with. I wrote another post about it here

But to me, it seems like these changes will make him insanely bursty, but with even smaller windows to do damage. I think overall this is going to help his laning significantly, and hurt his teamfight. 6 seconds was definitely a little too long, but I think 2.5s might not be enough.

I think the main problem with Ryze was that his passive stacks allowed him to have pressure for a little bit too long. That is, for the 12 seconds that he has 4 stacks of his passive pre-6, or 3 stacks post-6, You'd have to make sure to not be in range of him and let his passive wear off, and so you'd be zoned for a significant amount of time.

I think lowering the passive 5-stack duration to 4-5 seconds, and then lowering the stack timers from 12 seconds to between 5-8 seconds would have better effects. That way he's not stupidly bursty against squishies, and his teamfight isn't impacted so terribly, but it gives his window of burst in lane a much shorter period, and it forces him to use mana more quickly in order to build stacks.

Like Ezreal. Ezreal's 50% attack speed is absolutely godly earlygame if you've built full AD, but the buff duration is very low, and you'll go out of mana quickly if you try to keep it stacked, or if you try to stack it from 0-5 more than once. So it's a risk-reward scenario that's healthy for gameplay.