In model-driven engineering (MDE), models abstract the relevant features of software artefacts and model management operations, including model transformations, act on them automating large tasks of the development process. Flexible reuse of such operations is an important factor to improve productivity when developing and maintaining MDE solutions. In this work, we revisit the traditional notion of object subtyping based on subsumption, discarded by other approaches to model subtyping. We refine a type system for object-oriented programming with multiple inheritance to support model types in order to analyse its advantages and limitations with respect to reuse in MDE. Specifically, we extend type expressions with referential constraints and with OCL constraints. Our approach has been validated with a tool that extracts model types from (EMF) metamodels, paired with their OCL constraints, automatically and that exploits the extended subtyping relation to reuse model management operations. We show that structural model subtyping is expressive enough to support variants of model subtyping, including multiple, partial and dynamic model subtyping.