Believe it or not, Zephyr is an absolute must with Top Lane
. Literally every aspect of it helps his kit. You have the AD, AS, CDR, and Movement, not to mention the Tenacity. Depending how the game is going, I may even skip boots because of the 10% movement boost, and if you do want boots, you can get something that is much more suited to your teamfighting.
After many hours trying items in several games,
was the first champ I started using it on. It is possible to actually snowball with him top lane, you just needed the right build. Since then, I've spread out and begun building it on even more top laners, junglers, and even the occasional ADC. It brings a kit to the game that is not often utilized, but can completely change the way some champs can be played.
I do not believe the item is unbalanced because otherwise it wouldn't have lasted this long. I understand the new Tenacity rework, but I believe that would not be difficult to address given the course taken with said rework.
Riot wants to make it so each game of League feels and plays uniquely and I believe this item can help towards that goal. I believe the way to actually achieve this is by finding a way to promote player's to explore. To work outside of their suggested builds, not remove or introduce items.
Explore the items. You'd be surprised what dumb builds can work if played right.