Pure bias of a OTP here:
I've gone away and come back to Zac constantly for a while. Most other Zac players i talk to HATED the change and still are frustrated. So, with a blood stream full of caffeine I wanted to dump my/our thoughts to a more diverse group.
Why the rework? Zac was reworked during a mini tank overhaul. Tanks, especially then, were the same with different skins. An engage, hard CC, an AOE damage and/or debuff, usually a multi stun ult, and building health/armor/mr was good. They had/have very little mechanical play. Just keep walking around. Mumu, Ramus, Alistart, Malphite. All did the same but mildly different.
The decision was made to rework some of them. Give them more "skill" related abilities. Make them more unique. Cool. Good idea.
But, they turned to Zac. Who had a very unique engage (kept the same), and a VERY unique AOE stun ult that required positioning and thought to accurately succeed. His Q was garbage as a spell but was integral to Top lane.
What was done? His unique ult that could split a team up by knocking some back and some forward was replaced with his current one. At the time, you lost multiple damage hits and multiple blob spawns (healing during ult). His Q was replaced by another hard CC. Giving Zac 3. And, imo, the new Q is not really a skill shot. Often, you just Q a minion then auto a champ. His Q damage was nerfed hard. Can't have CC and damage, i get it. So, we have this new Zac. CC coming out of his ears and almost no damage.
What followed was a series of massive spikes and bottoms in win rates. 46%, 56%, 47%, 50%, 44% and has very slowly crept up to now at about 48.5%.
Zac is now a balancing nightmare. Give him damage.... broken. Can't have 3 hard CC and damage. High elo/pros will massacre. Damage is gutted and he's useless in solo q because that's how solo q is.
Zacs win rate from mid 2015 to mid 2017 bounced around (puns) from 48% to 52.5%.
Zacs play rate was about 4% rising up to 9% with the occasional patch block at 10 or 11%. The rework saw spikes to 13% followed by BOMBS down to 3%. Currently..... for half a year.... under 2.5% play rate.
I can't see any world where this is thought of as a success. Is current Zac awful..... no. I wouldn't say that. But he's super tough to balance around different ELO of solo queue and pro play. And the biggest issue is that old Zac was flat out better. More lane options (top Zac was a niche thing), could actually be a bruiser-esque guy when needed, could be balanced and changed without wild win-rate swings.
I'd have to say the only change Zac need was his Q. It was braindead. It was not interactive. I would have looked at making his Q into a more difficult but still damage dealing spell. Such as keeping the current grab and slow, followed by your autos doing more damage and having more range to that champ until they get away or time runs out. Kinda like grabbing someones collar and punching them over and over. Now attack moving is a thing. You made it a narrower skill shot, the enemy can dash or move away.
The worst part is, Zac was just more fun back before rework. Lets Bounce was silly and interactive and fun. And honestly, it had big play potential if positioned correct or you were able to flash with it. The puddle and scoop is a step back from that and is a much stronger group CC that if wombo combo'd (let's be honest this is mostly for pro play) is devastating.
Thoughts? Was the rework actually needed? Was zac better old or new to play with? Play against?