I think animancy and souls are not real science, it is more like science through magic. In a world with mages and druids nobody will use normal tools to explore things like souls.
The machines were also made with magic and only use souls as energy to run.
That would be an okay explanation if souls magic was on the background. Something you see everywhere but not really what the story is about. There are a few things on fantasy that are better not to bring much attention to it and magic is one of them. You once bring attention to magic and you open a can of worms. Having machines that fucks the souls of babies everywhere and can be activated by the soul of three dudes is just provoking alot of questions and don't provoke too much questions you can't or is not willing to answer or, at least, spend a good amount of time speculating about.
Take shadowrun for example, mana is a substance that come from the life force of people, plants and animals. As the planet earth there is alot of life, so there is alot of mana and channeling mana you can cast magic. During the ages, the levels of mana go up and down and when it goes down, magic stop working and powerful magical things have to hibernate to survive on such enviroment. It is a bullshit excuse for magic as any other if you pick it appart but shadowrun authors are smart enough to not bring this too much focus. "Yes, there is magic but don't pay too much attention to that... see the cool twisted spirit I created for you to fight with."
They shouldn't EVER had give away the nature of the gods, once you do that, you bring their nature into focus... ohh boy... that is another can of worms if you are too hasty and vague with explanations... worse you imply that animancy created them and they are made of souls... what brings the nature of souls into focus... bad, bad idea. Gods, magic and other supernatural things, you can have fun with them that is why fantasy exist for anyway but the plot should avoid revealing anything about them and giving away the nature of the gods. Worse, they did that on the first game of their franchise... that is a BAD idea. If ever I buy Pillows 2, I won't play ever more with a priest class because they detonated any mistery about the gods and made them dull as fuck.
Well, it's actually very much fine to explain and systematize magic. Problem is, as you said, you need to spend some actual time designing it and making sure there are no retarded plot holes. Fuck, give it to some giggling stoner frat boys once you think you're done just to be on the safe side. Common problem in Fantasy is that the writers goes "Fuck, I don't know, it's magic, fuck off" and then keeps on using it as deus ex machina for everything - refer to Eragon for a wonderful example of this. Magic
can make sense though - you just need to invest a minimal amount of effort to set it up as a logical piece of the setting.
Similarly, giving away the nature of the gods isn't a problem, the problem is that the story does
absolutely nothing with this mad twist. So what if they were manufactured? What makes this special? Why do we care? In fact, our party doesn't care one bit about this revelation, everyone nods along and says that yeah, they figured it was like that. Okay, and...? I guess if some of the characters would say, "We'll make our own gods, with blackjack and hookers, then!" or "What right do they have to dictate us, then?" or ANYTHING to protest this nature, the reveal would be justified. If only there was a point.
But nope - there is no point, that's the point. Apparently the message is, "Nobody actually cares if gods do not exist or were grown in a test tube, w/e". There's no payoff, there's no climax, and there's not even a setup for things to come. Only Durance says that he'll kill them off, but that's because he's our lovable mad sheep-shagger. And even then, he only wants to kill the "gods" that slighted him, not because they're all phonies, but because they fucked him over. What did this reveal accomplish? If there were a reveal about Woedica going mad due to some programming error, some Y2K bug, and that it's only a matter of time before others get it too, okay, that's kinda interesting, maybe. Maybe. If there's something that suggests a threat from the
artificiality angle (destroy all humans?), then it's maybe something. If there's a promise of greatness for mankind through development of animancy and guidance of artificial gods, then there's something. Or if the "gods" had found - or developed - a "devil", or an actual devil. I don't know. SOMETHING! Something to make their "special" pantheon be meaningful.
But there's fucking nothing. Absolutely nothing to work with. A Shyamalan twist for the sake of having a twist.