Should crimes of self-control be treated more harshly than regular crimes? Are they a bigger threat to the system?

Criminologists Hirschi and Gottfredson developed the "General Theory" of self-control, which states that an individual's lack of self-control is the largest factor that determines crime. They believe that self-control increases as a person ages because of biological factors (the development of hormones) and through socialization. Some studies, such as that by Vazsonyi et al. (2007; see the source below) have added validity to the idea that lack of self-control among individuals is a strong predictor of crime. 
Therefore, there is evidence that crimes of self-control are a large threat to the system. Individuals who are insensitive to others' feelings and who are impulsive are generally more prone to commit crimes. According to Hollander-Blumoff (2012; see the sources below), there are several factors that impede self-control, including medical factors present since birth or factors related to one's childhood or rearing. In addition, she writes that the punishment of crimes related to self-control should include rehabilitation:

"Self-control research in psychology also offers a suggestion for both prevention and rehabilitation: if self-control is a resource that can be strengthened over time with practice, perhaps this is a fruitful area for further development in our at-risk populations."

In other words, the best way to deal with crimes involving self-control may not be harsher punishments but prevention of crime by improving people's self-control and rehabilitation. 
Sources
Hollander-Blumoff, Rebecca E., Crime, Punishment, and the Psychology of Self-Control (May 2012). Emory Law Journal, Vol. 61, No. 501, 2012; Washington University in St. Louis Legal Studies Research Paper No. 12-05-22. Available at SSRN: https://ssrn.com/abstract=2080858
Vazsonyi, A. T.; Belliston, L. M. (2007). "The Family → Low Self-Control → Deviance: A Cross-Cultural and Cross-National Test of Self-Control Theory". Criminal Justice and Behavior. 34 (4): 505–530. doi:10.1177/0093854806292299.