Generally speaking, as I understand it the difference between 1st and 2nd degree is both are preplanned (or premeditated) but 1st degree considers the more diabolical element where the accused had TIME TO REFLECT but still proceeded. The States allegations that Jodi travelled from California planning the murder, then engaged in a sexual romp and photographic session meet the element of 1st degree........as opposed, for example, to the murder being committed after she slid unknowingly into the house and took him off guard. Even the drive from California to Mesa would be considered adequate time to reflect IMO.
Only Manslaughter meets the standards of NO premeditation, in someone was killed without any intent.
The State is clearly not arguing manslaughter or 2nd degree murder occurred or the death penalty would not be on the table.
2nd Degree is result of the passion or in Arizona it is the reactive aggression. The emotional reacting to a perceived provocation at the time. The intent is formed at the time of the crime. No premeditation.
As far as the horrendous nature of crime it has not been determined exactly when Travis died and exactly what killed him. The shooting. The throat slicing. The stabbing or some combination of the three. For instance, if one of the methods is solely responsible for his death the other two are not killing but mutilation of a corpse. JM is trying to make it seem Travis was alive through all three methods and greatly suffered until last method employed took his life and then again he says Travis was dead from one method when Jodi continued killing him with another method. Makes no sense. But the evidence does not support either version. They are speculating about exactly when Travis died and from which method(s). They are all over the place with theories but nothing conclusive for special circumstances.