Er, not sure what you're reading
@Byzantine. But I don't think that's the case.
Amy: bled out, body had cooled, she was dead before Taylor got on the scene. In fact, she died pretty much instantly. She still could have decided to stay dead.
Dragon: The hardware running her as an emergency stopgap failed, she was dead. Go directly to the afterlife, do not pass go, do not collect $200. The fact she had developed an actual soul means she would have actually had an afterlife. Amy and Taylor had nothing to do with her resurrection. Dragon was given a choice to return or not.
Emily Piggot: She took an RPG to the face. By the time anyone capable of healing her arrived, she was dead and gone. Taylor had to try casting Raise Dead, and Emily was given the choice to return or not.
Clockblocker: He was evicirated and his throat torn out by Hookwolf, and probably bled out in seconds. By the time Amy arrived he was also dead and
given a choice to return or stay in the afterlife.
Now, it's distinctly possible that Tia and her brother
can't bring back the dead unless they are a dragon. With Taylor, she died in the ambulance. I think it's mentioned that she was on the verge of soul death, in which case there wouldn't have been an afterlife either. Thus her getting merged with the spirit of a dragon who had died young. If she hadn't accepted Tia and her brother's offer, it's quite possible that the EMT would have been unable to revive Taylor.
EDIT: Also keep in mind that Raise Dead requires the person be willing to return. Naturally, player characters are generally willing to return to life. But it's possible for someone to opt not to return.