Flexibility in the metamodel-model conformance relationship and in textual and graphical model representations is a very desirable property for a modelling framework, particularly in the conception phase of a new DSL. Over the last few years we have witnessed the emergence of several prototypes that relax the rigid conformance relationship enforced by 3-layer metamodelling frameworks such as EMF and MOF, and that enable drawings to be interpreted as structured models. In this invited talk, I will summarise my experiences from developing two such prototypes (one graphical and one textual), I will discuss opportunities and challenges involved in flexible modelling, and I will present some thoughts on directions for future research in this area.