This means, on average, an Eldritch Blast will drop almost any 1st level PC unless they have obscenely stacked Con. If, for some reason, you were playing a hill dwarf fighter with a 16 Con and the Survivor specialty, you could have 23 HP at max; an Eldritch Blast could still drop you in 2 hits. Without Survivor, your 15 hp could be taken out by a single good roll. More normal characters will be looking at 6 to 12 hp, in which case you are very much in danger of an Eldritch Blast.
I know PCs aren't supposed to be balanced against each other, but what level threat would a 1st level human Warlock be, anyway?
Armor Class 13 (leather)
Hit Points 13 (1d6+2+1d8)
Speed 30 ft.
Str 9 (-1) Dex 14 (+2) Con 15 (+2)
Int 18 (+4) Wis 13 (+1) Cha 11 (+0)
Bounty Hunter: Stealth (+3), Spot (+3), Streetwise (+3)
Ranged Attack-Eldritch Blast: +4 to hit (range 50 ft.; one creature). Hit: 3d6 force damage.
Warlock Invocations: The warlock can use any combination of the following invocations twice per encounter.
Area Attack-Baleful Utterance: 15 ft. cone; each creature in cone. 2d6 thunder damage and deafened until end of warlock's next turn; Constitution save DC 15 for half damage and no deafened. Unattended objects in cone take maximum damage.
Ethereal Stride: The warlock becomes ethereal until the end of its next turn. An ethereal warlock has a spectral appearance, takes half damage from non-ethereal sources and deals only half damage to non-ethereal targets (neither effect applies to force damage), and the warlock can pass through non-ethereal creatures and objects (but is blinded while in an object and cannot target anything but the object).
So, again, I know players aren't built on the same track as monsters, but that's a very challenging foe compared to other creatures. 3d6 damage is a ton.
Poe's Law is alive and well.