I like where you're going with this, but some stuff might be a little overpowered. Here's what I like and dislike.
Patron Spells: I like that you added the Patrons spells like every other class does. I don't think warlocks need the extra spell slot though. The reason is why is, warlocks spells are already an unlimited resource, granted they are limited by how many you can use in a fight, they always get them back. Let's not forget, as you level up, the warlock will be getting magic items. Staves, robes, and wands add tremendously to a warlocks arsenal. Also the Rod of the Pact Keeper gives him a spell slot back.
Invocations: with the 1/day spells, again I feel the extra slots are not needed, if you do that, someone is just going to start stacking them for extra slots. Keep in mind that when they created the warlock, they want to create a caster whose spells was an unlimited resource. The invocation spells are supposed to be big spells that are actually limited. I think they could've added a couple more cast at will spells though. But remember, there are a lot of warlock friendly races that also have racial spells.
Now your meat and potatoes Pact of the Blade:
What I like:
Medium Armor at 3rd
The 2 invocations although, I think those should last until the start of the next turn, and shouldn't be you can only have one or the other.
What I don't like:
Making multi-attack automatic. While I see where you're going with this, I find it to be unnecessary.
I don't think warlocks need CHA to replace STR & DEX. It's a balancing issue, because all of the other hybrid classes still have to balance their stats, warlocks need to do the same. Besides, they get Life drinker at lvl 12.
I don't think you should ban agonizing blast from PotB warlocks, it maybe highly suggested, but ultimately it should be the player's choice on how they build their character.
Warlocks should not get a fighting style. Fighting styles are 5e version weapon specialization. Only1 the warrior classes have it, and only they should get it.
While EKs fighters with some magical ability, bladelocks are casters with some fighting ability. They have different roles. While the EK is good on the front, the bladelock should be in the back protecting the casters, or behind the warrior's taking out the trash like rogues.
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