Muir, who is involved with the Seam project and was the project lead for the JSR-299 (Context and Dependency Injection) spec, says that the primary blockers are getting Weld Extensions and XML Bean Config API. See below:
In a previous interview, Muir told DZone that Seam 3 would be a major advancement over Seam 2's programming model. Seam 3 will also support the legacy applications from Seam 2:
What we'll do is we'll emulate the Seam 2.0 functionality running on Seam 3.0, so you can run your Seam 2.0 apps natively. And we're going to be looking for a lot of help from the community on this one too. We're going to need to identify what are the major APIs that they use in Seam 2.0, so that we can port those first and get those running first.
Muir also mentioned some of the performance and scalability enhancements being implemented in Seam 3:
There have been a number of minor performance and scalability enhancements made to Seam since the 2.0 release. We did some performance analysis, some scalability analysis ourselves. And there were quite a few improvements to the Seam code base… It's all very well saying that you can optimize the implementation, but there were a number of design problems with the Seam core that were very hard to work around, to get excellent performance out of it… So with 299, we were actually able to take all of these lessons and build them up to a performant design, so things happen in a much faster way. That was really the first thing, I guess, that we've actually improved the performance in the build and design. The second thing is, again, we've taken the lessons from the core implementation and integrated those into the CDI release.
Keep an eye on jboss.org for the Seam 3 beta, which features innovative tools and modern new features that have undergone more than a year's worth of development.