Let's talk about Zilean's passive/Rework Idea

Ever since Zilean's passive was changed from global to local with no compensation buffs, his winrate has been in the gutter. The recent rework has helped to bring some more potential power in his kit, but his passive remains the same and if the massive drop in his winrate was any indication, it's definitely the weak part of his kit at the moment. I'm not sure why they decided a support with a healthy 51% winrate needed such a drastic range nerf without any form of compensation, but Riot has made it clear that they are not going back to global passives. But Riot cannot just keep the range and buff the %XP bonus as it is right now, as this could potentially be oppressive and make bottom lane more 'snowbally' than it already is, and combined with fast scalers like it could actually be gg at first blood, so simply increasing bonus XP is not the solution at all.

Another problem with his current passive is that it locks him out of midlane if he wants to make the most out of it. Back when his laning pattern boiled down to "I'm going to right click on you" I could see why Zilean shouldn't have been allowed to boost his team's XP and still be in midlane, but now that his rework has introduced skillshot bombs, I think he could be a healthy support that can also function as a healthy midlane mage, allowing him to be more of a flex pick mage-support like we have seen with lately.

Yet another problem with his passive is it's relevancy throughout the game. The additional XP gain is most impactful during the early game, where teamfights are minimal and at most one ally will benefit from his passive. By midgame, Zilean would have to be right next to all of his allies in every single teamfight (and keep his squishy ass alive the entire time) to make the most of his passive, which is unrealistic and anyone who is specifically playing around his passive is encouraged to sit in the backline and take as few risks as possible, solidifying his unfavorable state as a GA bot and making the fights uninteractive for both teams. What is possibly the weakest part of his passive is that it is nonexistent late game. As much as I personally dislike on-death passives (I believe you gain no benefits for playing well and not dying), at least they can have a decent, sometimes significant effect in late game teamfights, whereas Zilean's passive does nothing once his team is lvl 18.

My idea for a rework to Zilean's passive is this: **On ability use, Zilean reduces the remaining cooldowns of him and all nearby allies by 5%. **

I'm no game designer and the numbers might need adjustment, but I think a new passive along these lines would be a much better fit for Zilean. This would solidify him as the cooldown support and give him reason to actually use his abilities in teamfights and take risks instead of just sit in the back and press R on whoever is about to die, which is what he does now. This passive would be useful past level 18, it would give him unique utility during all stages of the game, it would have the greatest effect in teamfights, where supports are meant to shine, and during gameplay, people would feel like time really does "pass faster" when near Zilean, which I believe would be amazing considering his theme.

First post I have made suggesting game design, so please leave feedback, and criticism is always welcome. Feel free to share any thoughts or ideas of your own.