Although the eFFBD formalism dates back to the 1990s (or even, in a simplified
form, the 1950s), it seems that it is still not as much used by the Systems Engineering community as it could. Indeed, eFFBD is a modeling language focusing on functional paradigm
i.e. allowing functional and behavioral modeling and reasoning about a system. Currently, it
is often confronted or compared to other languages such as SysML for activity modeling (activity diagrams) based on object paradigm. This paper aims to demonstrate the interest and
the potential advantages for systems designers, like most of the discipline-oriented designers to dispose of an enriched (conceptually and semantically) eFFBD modeling language called here xFFBD. This has to be a credible framework for modeling, communicating and reasoning about complex systems. After shortly recalling the history, the key concepts and capabilities of eFFBD, this paper compares eFFBD with other formalisms considered here as relevant for the study, Petri nets and SysML. Several leads are then identified and discussed in order to improve the eFFBD language and to provide a first draft version of xFFBD specification
