Molenaar's (2015) article concerns Developmental Systems Theory (DST) in relation to behavior genetics and he presents implications of DST for empirical research, especially the need for subject-specific studies. In this commentary, the article is discussed from a broader developmental science perspective, particularly regarded through the lens of the person-oriented approach. It is pointed out that a pattern perspective is given little attention, although it is central to many modern theoretical frameworks in developmental science. The quest for models that match DST theoretical conceptualizations is also discussed, for instance the basic endeavor to find a universal model and the need to clarify what constitutes good model fit. [This commentary relates to Peter Molenaar's "An Interpretation of Part of Gilbert Gottlieb's Legacy: Developmental Systems Theory Contra Developmental Behavior Genetics" (EJ1144157).]