Stupidity: Why is it that runners wait until their 30th birthday to run, when they'll most likely get caught? It would make more sense if runners tried to escape to sanctuary weeks or months before their last day. This way, they could meticulously plan their escape without drawing attention to themselves.
Suggested correction: That wouldn't be particularly advantageous for runners. The computer system monitoring the city knows when someone is running regardless of their age and will dispatch the Sandmen to eliminate them. People who choose to run only do it as a last ditch effort, believing they will die on Carousel anyway so running is a risk some are willing to take. In the meantime it would be preferable to live out their guaranteed lifespan and enjoy the pleasures afforded to them by living within the city.
Stupidity: The babies could have simply been swapped at the start. There was no reason Father Spiletto needed to inform Robert Thorn of his son's death and then convince him to take a different child instead.
Suggested correction: Perhaps, but then again the Satanists were trying to cover all bases. If they simply swapped them, the parents may start questioning things when Damien grew up and they might have noticed that he didn't look or behave like either of them. For insurance they could have brought Robert Thorn into the plot (without his knowledge of the full story), so that if she asks any questions he could simply stick to the story, offering a cover to the Satanists. During the conversation, he mentioned that the baby dying would be devastating to his wife (which is why he agreed to the switch) so his intentions were pure, even though it ends badly and tragically for both him and his wife.
