Essence Reaver suggestion: anti-mage melee AD item.
Right now, there are only 3 champ types that actually matter: AP mages, AP tanks and ranged ADCs.
top solo queue win rates are pretty much AP tanks, AP mages and ADCs. Most challenger players are ADC mains. In the LCS, ranged AP tops are dominant and the only AD mid that matters is Zed.
The reason is simple: there is essentially no way to counter itemize for sustained magic damage in the late game. Most AD bruisers cannot actually outdamage tanks late game due to the way itemization and base resistances work while having far inferior utility. The only way to beat APs is to beat them in lane such that they never get to late game (Zed) or to assassinate them before a fight even starts so they have no ability to output their damage (most AD bruisers/assassins). However, late game, they don't need to really put themselves at risk to deal damage. All they need to do is peel for the carry, self peel with Zhonyas and the rest will take care of itself.
That is why every AP assassin has been incredibly toxic when strong: Nidalee, Akali, Fizz, LeBlanc, Kassadin, etc. have been incredibly broken before some of their horrendous number nerfs and banned far more than analogous AD assassins like Zed, Talon and Kha'Zix - they are simply way harder to itemize against.
I suggest an anti-AP item that ADCs do not benefit from (to keep them risky, in exchange for literally being the carry class) while benefitting other AD champs who frankly need help at this point. It also fixes the problem of Essence Reaver being trash and only good on 3 champs.
Essence Reaver Faerie Charm + Hexdrinker + Brutalizer + 333 gold (3300 total)
UNIQUE ACTIVE - Magical Thirst: Deal magic damage to enemy champion equal to 50% of their total AP. Gain that much mana. Excess mana is stored as a mana shield that absorbs damage (90 second cooldown). UNIQUE PASSIVE - Lifeline: Upon taking magic damage that would reduce health below 30%, grants a shield that absorbs 250 magic damage for 5 seconds (90 second cooldown).
+100% base mana regen +55 AD +10% Cooldown Reduction +10 Armor Penetration +35 Magic Resist
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, and a few more I'm sure could really use a way to actually do damage to AP tanks or to be able to take out an AP mage before they kill you first, depending on what your champion's main role is.