I'm currently playing a hexblade in a guest chapter in one of my games, and I've run into a problem with the archetype as-written: it's a little too evil. The "Accursed Specter feature at level 6 lets you "curse the soul of a person you slay, temporarily binding it to your service." The problem is two-fold: most of the denizens of a d&d world are likely to regard raising the undead as evil, and the ability strong incentivizes killing other humanoids.
While I've had a few reasonable debates (and several pointless and unreasonable ones) about whether raising the dead is Evil (aligned with the D&D moral absolute), I've heard no solid arguments yet that the population (and most adventurers) wouldn't consider it to be evil (dark, wrong, horrible, disgusting). While there are plenty of Hexblade concepts that would be fine with that, there are also plenty that would find it problematic and repugnant. Mine falls in the middle of that spectrum - he has no problem with necromancy itself, but is unwilling to suffer the social consequences of being seen as a necromancer.
As a secondary point, the actual abilities of the Specter are pretty dark themselves; Life Drain and Sunlight Sensitivity are both decent indicators of Evil in-game.
This appears to be a deliberate flavor injection by WotC; it does make sense that a Hexblade would be expected to kill by its patron. But specifying "humanoids" adds a moral dimension to the ability that concerns me. At a game-universe level it can make sense, presumably non-humanoids don't have the right kinds of souls or something? But it unfortunately makes the ability nearly useless of Good characters - they almost always prefer capturing humanoids over killing them. If the Hexblade is not the good character in the party, it sets up an equally irritating recurring moral conflict, where the warlock is arguing for the death penalty just for his own benefit.
My interim DM and I chose 32 as being the least balance-affecting. Its attack will be the same, but reskinned as it swinging a spectral greatsword, and I'm dropping the "drain" part off of the attack.