Software and system architecture modeling is a well-established technique for addressing design-time challenges and enabling validation early in the system and software development process. However, software and system modeling has not been as widely used in automation systems as it has been in the automotive industry. In addition to validating functional properties through modeling, security properties and features can be evaluated in the modeling phase. This paper provides a brief overview of existing modeling approaches for future automation systems, known as modular automation, that support security modeling and analysis. Modular automation refers to a new trend in automation in which various modules are developed in advance and integrated to build an automation system. Moreover, we study the gaps and missing components of the existing modeling approaches via a use case demonstration. Our study shows that the current state of automation and control system modeling has several limitations that require urgent attention.