Zed is not unbalanced, playing against him is unbalanced.
Here me out community before the shitstorm of downvotes! Before I start, I do play Zed and I really really like to play Zed. He's a good champion with strong dueling power, but lacks teamfight ability. I'm not here to defend him, but the problem is not Zed. Zed, as a champion, is pretty balanced right now. He can outplay you, but you can outplay him. He's very squishy, but is a strong 1v1 duelist. He's mobile, but not completely overbearing. You can itemize against him late game with Hourglass and Mecurial. The problem with Zed lies in his early game dominance that cannot be contested by any current champion on the roster. Here is a prime example of why Zed is completely overbearing.
Mid lane, you have a couple of options against zed. You can play an AP Mage to try and poke safely, while being able to provide more teamfight utility for later in the game or try and play another assassin like LB/fizz and hope that you burst Zed down before he kills you. I'm going to focus on the Mage aspect, since half the LOL roster can be identified by "ap Mage" There are a few items that you can start to build against Zed. Here are the options.
. You can rush armguard against Zed. This component ends with Hourglass, which is a GREAT counter to Zed's burst damage. The problem with rushing armguard lies in a couple of reasons. 1) you lack mana sustain and CDR. This means as a Mage, you're forced to conserve mana and poke only occasionally. You're forced to farm under turret, losing precious CS, while Zed gets to shove lane and roam freely. You are forced to ask your jungler to camp your lane and hope and pray that Zed is not smart and plays too aggressively. Also, if you rush all Zed has to do is rush 
and throw in arpen runes/masteries and you're basically countered. Access to easy arpen makes seekers a risky rush, especially when you factor in the amount of farm lost and roaming time lost because of the lack of mana. TLDR: Seekers is easily countered early and is too risky for mages to rush.
and the smaller components are another option against Zed. These components give access to the Mage CDR/AP and mana regeneration. This allows for the Mage to help mitigate the mana gating problem, allowing for waveclear/poke and forcing Zed to farm under tower. The issues with a Morellos rush are many. 1) zed can easily farm under turret. He can play passive and wait for a jungler gank, while the AP mage like Lux, Ziggs, Xerath and Orianna. These mages get eaten for breakfast by the likes of J4, Vi, Lee, rek'sai, xin and Hecarim. It's a real risk, seeing as Zed can use his mobility and react to the gank quickly, allowing for him to score the kill and snowball lane. 2) rushing Morellos gives purely offensive stats, the problem with that is Zeds all in potential between levels 3-6 are that much more deadly. Also, with easy access to his all in becomes deadly and you risk losing your lane very very early on in the game. TLDR: Morellos is a good buy, but does not give the Mage enough tools to deal with Zed's lack of mana gate, his mobility and all in potential from as early as level 3.
The solution to Zed also applies to all AD assassins that are not gated by mana, Riven comes to mind. This change is a new item that will help mages combat with Zed in a way that's fair and allows for mages to be able to match Zed's power and help mitigate his huge power spike at level 6.
Make an Athenes specifically used to combat against AD assassins. Allow for the same components as Athenes, except swap the null magic mantel for cloth armor and adjust the price accordingly and vullaaaa. Mages now have access to ap/mana regen/armor and CDR. Mages can now compete with the manaless harass from Zed, while being able to poke him down and hopefully secure a kill. Zed now has more counterplay to his early game and he finally has to make a conscious choice when he engages rather than the typical "I'm level 6 time to all in my enemy mid laner and snowball lane!"
Would this be a good idea? I'd like to see your opinion on the matter??
