Alex Henderson picked up on my "Why O Why" post in his take on the Pluggable IoC in WPF Composite & Enterprise Library v.Next.
I still believe that an IoC Application Block in the next version Enterprise Library is not a good thing. There are a number of very talented people working on existing open-source DI containers for a long time now. Their efforts do not only involve providing source-code to these open-source projects, but also teaching a community on how to write better and maintainable applications. Instead of rewarding and honoring these very talented guys 'n dolls, Microsoft decided to ignore their work and provide their own (Oren has a point here).
Isn't it possible for the P&P team to pick the three most commonly used DI containers out there, write a provider model for them and use these in the Enterprise Library and the WPF Composite framework. Provide the means for other DI containers out there to write providers of their own so that their communities can use the P&P stuff with their own favorite container. How hard can it be? Maybe I'm being a bit too simplistic about it, but I hope you'll get my point here.
I agree that providing an IoC Application Block in the Enterprise Library would reach a lot more developers than is the case today. But a completely new DI container written by the P&P team only adds to the underlying problem here. This underlying problem is the fact that most developers in the .NET community only look at what is coming from Microsoft and that's it. If the P&P team would have the courage to stand up, provide some existing DI containers out there today, these developers could come to the conclusion that the .NET community != Microsoft.
Scott Gu seems to get it! Not only by opening up the ASP.NET MVC framework, but providing support for the xUnit frameworks that exist out there today.
I shiver on the thought of what is next. A Mocking application block? My two cents.