In the last few years, almost all model-driven Web Engineering approaches have evolved in response to the new challenges of Web systems design, which are due to new requirements and implementation technologies in the Web domain. The evolution implies the extension and adaptation of current approaches, in terms of new models, transformations and processes in order to incorporate new concerns or aspects. Such changes in a methodology are a risky and error-prone process. In this paper, we analyze different alternatives to address the evolution and in particular, the addition of a new concern in a Model-Driven Web Engineering approach: (a) extending the original method with an additional modeling concern, (b) merging the original proposal with another approach covering the specific concern and, (c) finally, we propose a an interoperable and architectural-centric approach that aims to reduce the impact of adding a new concern. We discuss the main advantages and drawbacks of each alternative...