A summary with some numbers I have looked into by comparing with existing the Hexblade class.
HP
-60 HP from Hit Die reduction (-20 if Mortality Undone is taken)
AB
-1 AB from Curse Weapon (from +6 to +5)
+2 AB from Hex of Hallucination
-2 from default Hex (old Hex gave -5 and Hex of Rust gives -3)
-1 when all considered
Physical DI
Down to 10% from 18%
Physical Vulnerability
Up to 20% from 15%
AC
+2 from Hex of Rust (none previously)
-2 Hex of Hallucination bonus down to -3 from -5
AC neutral from what I can see.
Atrocities
Atrocities will end with around 31-33 DC (+2 for Whispers + 4 for Invocations) with an additional +4 from Woe Drinker, which bumps Invocations up to 41 DC and Strikes to 37. In this day and age, the side effects will only fail on a natural 1 as is the issue with other spells relying on DC. Immunities also apply. With that said they do provide some utility in ranged effects that the Hexblade did not have before.
Spell List
Definitely better, the addition of Grease, Cloudkill and Breach are the best additions. Death Armour, Lesser Mind Blank and Lesser Spell Mantle are also nice but likely not worth the cast as they will be immediately be breached in PvP, better saving those slots for Hastes and the offensive breaches and cloudkills.
The Paths
These are really hard for me to evaluate, they all look fine with no major contender, just doing different thematic things. Black Blade of Disaster without concentrations checks has potential to be really good.
Some of the on-kill bonus are weird. In PvP they don't fit a role as you will not be killing people left and right. It incentivises me to summon a rat, Dark Claim and kill it for the bonus and then wait for Dark Claim to come out of cooldown so I can start whacking with the bonus.
Hex and Curse Feats
I generally like these, most of the old ones remain and with some new ones giving different possibilities.
Hex of the Hex-breaker Hex of the Oathbreaker and Hex of Arcane Hunger are all really good.
Greater Weapon Hex, Improved Weapon Hex and Improved Dark Claim to not convince me. The Weapon Hex feats would stack up to 2d8 Elemental damage, 5/- being blocked by defensive essences. Massive Criticals and SR are nice but likely not worth the feats.
Improved Dark Claim is not amazing, the issue with Dark Claim's cooldown is not the d4 part but rather the 1 turn. If it cut it down to 30 seconds as the current Hex is it might be worth it.
Mortality Undone reducing DI from 18% to 10% seems unnecessary, Hexblades always needed that to be competitive and not die as easily in both PvP and PvE. Even the EDR build still died quick enough to your average weaponmaster.
Are the new tools worth the loss of HP, AB and DI? I am not sure.