This is a mook vs big creature sort of thing and it is +5 AC with half plate. That AC will do more than the THP will ever do. Monsters tend to do big damage in 5e.
5 attacks for 1d6 is the same average damage as 1 attack for 5d6. Both in terms of AC and THP.
But let's say a level 5 warlock, with 18 Cha, 14 Con, 14 Dex, and 36 HP. (Though you can get 16 Dex/Con with a half-elf).
Attack by a CR 5 wearbear, with +7 to-hit, 13 damage, 2 attacks. (attacks favor armor, so i'll only count 3 kills per short rest)
Hex = 19 AC, 40% chance to be hit * 13 damage *2 attacks = 10.4 damage per round.
36+9 heal *3 rests = 63 effective HP
63 / 10.4 = 6.06 rouds until dead
Fiend = 14 AC, 65% chance to be hit * 13 damage *2 attacks = 16.9 damage per round.
36+9 THP*3 kills * 3 rests = 117 effective HP
117 / 16.9 = 6.92 rounds until dead
Fiend survives 15% longer. At the cost of some damage.
Call it a tie.
Don't forget the increased crit range either.
0.05 * 5.5 = +0.275 damage per ray. About half a point of damage with advantage.
It's pretty forgettable.
The Fiend's 1st level ability is the strongest of the lot, but remember that the THP won't stack so they actually want to take a lot of attacks if they are picking off mooks for it to be effective.
A good thing to do with multi-ray eldrich blast, avoiding overkill. Or with a fireball.
But yea, hex wins if your DM likes single big monsters. Both in terms of damage, and the lack of minions for fiend to feed off of.
THP on creature kill is worth an invocation (about as good as at will False Life only it scales so it keeps being decent)[/qoute]False life takes an action. Fiend can recharges mid-combat.
But you can calculate again. Hex with false life, and fiend with mage armor.
Telepathy would be one of those invocations that might be taken for some utility/flavour but not often. I think I would rather have 2 skill proficiencies or at will Disguise Self.
Charm/Frighten 1/round for an action probably wouldn't even be taken as an Invocation at all.
Agreed. Hex beats fey and goo for dungeon crawl games.
Again, hex is A top sub-class. It's just not THE top sub-class. It ties on features, but loses on spells.