Sounds to me like her boyfriend (the dude she murdered) strung her along for quite awhile (even after he dumped her) so he could continue to have deviant sex with her (in the butt) while he looked for a good Mormon girl he could marry. Now, I am in no way saying he got what was coming to him, but neither is he completely blameless.
They were both lacking in moral character, IMO. She a gold digger, he using her desire to land him to get her to perform deviant sexual acts. Then he cut her loose, but continued to use her for sex? It must have blinded him to how crazy she was (and still is) that she'd go along with whatever he wanted in the sack.
So should she get the death penalty? Not being a criminal-coddling lefty, I think it would be appropriate. From what I hear there is a good possibility she'll fry. The anti-ultimate justice Libs no doubt believe she should get counseling and be rehabilitated. Frankly I think rehabilitation isn't possible with many criminal types and not at all with mental defectives like this Arias chick. Not that I believe she didn't know what she was doing and should get off for that reason (insanity).
In any case – this should, perhaps, be a lesson to the single guys out there (who are completely lacking in morals). If you want to use a woman for sex and string her along for an extended period of time – make sure she isn't a psycho nutcase first.