In this paper, we study the added-value of visual languages when used to design the learning scenario of Technology-Enhanced Learning (TEL) Systems. We particularly focus on the conceptual models that designers can produce from such visual instructional design languages. Several benefits are identified and discussed. First, such visual languages are well fitted to help designers explore the requirements of TEL systems ; such languages also enable designers exchanging different viewpoints in order to reach a viable technical solution. The discussion section pinpoints that beyond their graphic features, visual instructional design languages should conveniently mix adequate design primitives with stratification and multi-perspectives capabilities.