The Eclipse Riena project, currently in the proposed project state under the Eclipse Technology umbrella, represents a proposal written to garner feedback and participation from the Eclipse community. Thus far, the Eclipse Rich Client Platform (RCP) is a proven and solid foundation for building rich client applications. And its increasing maturity has drawn attention from the realm of enterprise application development. The Riena project, as a proposal, is the natural progression of the open source momentum behind the Eclipse ecosystem. Plus, there's something to be said for targeting the needs and realities of multi-tier enterprise applications using open source.
Overall, it will prove intriguing to monitor how Riena matures as an enterprise application development platform. Especially when compared to the historical growth of Eclipse as a general platform for software development. Specifically I wonder how a significantly smaller user base for Riena will effect its ability to develop a vibrant surrounding ecosystem. Partly I'm not sure how much more the general Eclipse ecosystem will overlap with Riena's focus area. Furthermore, it will prove challenging to actually engage a wider aspect of the enterprise application development spectrum as end users. Obviously Riena will potentially pay huge dividends to companies, like CA which has already based new Harvest clients on Eclipse RCP, but will Riena become capable of attracting a larger hunk of enterprise application developers that aren't already using Eclipse? It might have to in order to reach a reasonable level of critical mass.
Eclipse has been successful precisely because it has emerged as an open platform for different forms of software development. A "long tail" effect amongst its ecosystem of Eclipse based products, plug-ins, etc. has powered penetration into many an IT shop. Riena, as one such Eclipse descendant, will count itself as a benefactor of this reality. Yet it also must find a way to forge an identity based on a unique value proposition aside from being a member of the Eclipse umbrella. At this juncture, most of these questions are out of scope but at some point the answers will determine what becomes of Riena as a project and effort.