Wouldn't it be a good idea if the breaking change to the ProxyFactory would be mentioned in the release notes? It's quite a big change that you don't need (and have) that seperate assemblies any more by default.
And there is not only the compile time breaking change. If you have previously used Castle and your entities use the quite common GetUnproxiedType() trick (e.g. from Sharp-Architecture or the NHibernate 3.0 Cookbook), there will be a bug in your code if you switch to the new default ProxyFactory (because that GetUnproxiedType() trick doesn't work with it, like it didn't work with LinFu and Spring).
