Based on our research concerning Finnish national enterprise architecture (EA) adoption in long run, we discuss here how EA concept and tool are to be developed to support business ecosystem and organization design. Our research context indicates, beyond a federal government or a state one, that even a single municipality, like a city concern, can be perceived as an ecosystem of its sectoral domains, subsidiaries etc. We outline a vision of an overall ontologybased, shared EA repository for the-whole-of-government current state descriptions. We specify the central design principles and functional requirements for such a system and illustrate some potential use cases of it. The study suggests further abductive studies on the best design for such a system. Consequentially, we propose EA as a concept for organizational design of a government entirety.