Is Enterprise Architecture a Role or a Skill? As the adage goes ask 10 IT Executives and get 11 answers. And that hints at a broader problem facing Enterprise Architecture in the industry of whether the discipline is worthwhile. Enterprise Architecture as Strategy avoids the question directly but comes as close to anything I've read to the answer.
The essence of Enterprise Architecture as Strategy comes 47 gripping pages in:
Many companies attack the enterprise architecture exercise with lots of drawings and analysis of both existing and hoped-for systems capabilities. But massive analytical efforts do not focus resources on what matters. The key to effective enterprise architecture is to identify the processes, data, technologies, and customer interfaces that take the operating model from vision to reality. 
By then we've explored operating models, multiple successful examples*, and come to realize this is a book about making change. In that way it stands out from a lot of enterprise architecture books and training in that drawings and catalogues are merely a tool to use not the sole focus.
There was a point in my programming career when I stopped focussing solely on programming skills to read The Pragmatic Programmer and it transformed my understanding of the place of programming in an organization. Enterprise Architecture as Strategy is similar in that the focus is on the application of skills to have a broader, more rewarding output.
Operating models are determined by two axises; Business Process Integration (y axis) and Business Process Standardization (x axis). At the bottom left where there is little integration or standardization is Diversification, heading up the y axis is Coordination, heading over on the x axis is Replication and where there is both integration and standardization is Unification. In less dry terms; Diversification is a holding company, Replication a franchise, Coordination "benefit from some cross over", and Unification "one way leads to success".
A model can apply to an entire organization to a business unit all the way down to a parts of a business unit. And this flexibility of deciding what portion of an organization to consider and then picking a model is a key to success.
There are four levels of maturity; Business Silos, Standardized Technology, Optimized Core and Business Modularity and in each the control of what an application/process does and who decides on budgets changes. Projects across departments often fail because while they want the same tool they want to use it in different ways. Combing an operating model with an understanding of the maturity levels of each affected group provides a framework for the execution of a successful project.
So, Is Enterprise Architecture a Role or a Skill? The answer is both. For an organization to be successful all top leaders need to understand the skill and to help with focus there needs to be a team dedicated to it. Like everything in Enterprise Architecture as Strategy this is backed up by research. 
* Including the local government of where I live Washington D.C. in 1999 under CTO Suzanne Park on pages 16-20.
 Enterprise Architecture as Strategy, p. 47
 Enterprise Architecture as Strategy, p. 101, 110