I guess we disagree. Personally had zero interest in backstory lore. The show wasn't about the angel and no explanation was necessary.
I agree and disagree at same time
I mean vampire backstory lore was not needed, but not because he's not been a big piece or because backstory in his case was irrelevant
For how i seen it vampire's backtory being purposely omitted was big deal, so we had the chance to see the priest filling this void with his faith and see with his eyes the vampire becoming an "angel"
regarding the main villain and the decided to go a low intelligent and animalistic route.
Wich is not true
You're simply making assumption he was dumb because you did'nt seen him on screen explain his plan moves etc
Reality is he managed to manipulate the priest to get him out of the cave, to bring him in america, to prepare the ground for him to be sold as an angel, handled his own blood to obtain mutations on humans to the level he wanted and even took part of the church farce where he got all dressed to play the part
If plan did'nt failed next move would have been the continent with his band of vampires and would have done crazy numbers before people started realize the fuck is going on
Had different brain for sure, but not inferior
If anything felt good amount of him not showing much conventional communication is because... he does'nt care, maybe even hate it. Watching the powers he showed was like a tiger next to rats and likely seen himself that way even if he showed to know he needed rats collaboration to get more rats
He had animalistic side (up to completely lose control when drinking, wich fucked his wings), but he clearly shows he knew how to manipulate humans, their mental weakness and herd mentality shit
Given time he would have probably learned to talk current language if he felt the need, we seen he was able to mimic voice... probably a bait trick he learned to confuse human prey, but given other signs of intelligence he showed it's pretty possible he was also "studying" current language
Plus of course he seems perfectly aware that ability to communicate or not, his physical appearance alone needs huge psychological foreplay on the population (in fact he used human ambassadors)
If anything reason the show seems to hint for his fail was'nt him not being smart but simply that he sleept too many centuries, and lot of his aura that used to trigger blind faith in gods/supernatural beings got crippled by modern times atheism
Not casual key peoples that made his plan fail were atheist, later followed by a guy that had diffidence being of a different faith
Dude showed up with a strategy that probably served him well plenty of times, got incredibly unlucky with the historical period timing
Plus of course got also bad luck have most atheist guy of the island spot him, forcing to act, wich leaded to group of resistance.
But tbh was'nt much bad luck alone, there was definitely the element he never felt in danger of fail (arrogance/onnipotence vibes)... in fact got caught because just casually left the church door wide open as acceptable risk
All this if we want assume the director want say there's no God and humans did all themselves.
If we wannt consider in director's mind God exist, vampire was just fooked because humans (at least some) have been designed so well by him that even using their free will and no God's magic help they still will win