Edge of Night will create a Huge Discrepancy between AD & AP Itemization: Please Don't Add it
This is truly one of the worst designed & most overloaded items I have ever seen. For a mere 3100 gold you get: 60 AD, 35 MR, 20 lethality, 20 out of combat movespeed and the active.
Earlier in season 6 there was an issue with Maw/Hexdrinker in that when an AD assassin built it against an AP Mage/Assassin they were almost certainly not going to die in lane or fall behind. I think this new item is intended to get rid of that issue by pushing Maw towards fighters and giving assassins an item that will give some MR, but not so much that winning lane against them as an AP champion becomes impossible simply because they build the item. The problem with that? It's going to make things a lot worse, because assassins are going to build it anyway. Maybe not necessarily first, but they will build it. Hexdrinker alone is a very effective item, you can absolutely expect to see the likes of Zed and Talon to grab a hexdrinker along with edge of night in AP matchups. Because when you are ahead, building defensively is a great way to ensure that you stay ahead. And although it will no longer provide armor pen (lethality), 50 AD for Maw is still plenty.
But wait, there's more. Not only will AD assassins abuse this item, we will see adcs and fighters build and abuse the item as well. There's a fed Master Yi or Wukong on the enemy team? Welp, good luck dealing with them now that they get a free banshees veil every 30 seconds that can be channeled while moving. Fed Nocturne? Have fun dealing with him as he blocks not 1 but 2 of your spells. Laning against Jayce as Rumble or Kennen top lane? Have fun trying to kill him through Edge of Night + Merc treads + hexdrinker. Laning against Talon as Veigar? Welp, his shield will block your stun and you wont be able to land your W, so you will automatically lose the all in. Not to mention what this will do to Karthus, as if there weren't enough ways to deny his ultimate already.
Between Maw + Mercurial Scimatar + Edge of Night + Merc treads AD champions will have a plethora of tools to outright ignore magic damage if they choose to without heavily impacting their damage. In contrast the only real option AP Champions have to itemize against AD champions without massively gimping their damage is Zhonyas (and it still requires a trade off as it is now one of the lower AP items).
Riot, please don't add this horribly designed item. I think you can come up with a better option for AD assassins that wont get abused by literally every single ad champion.