Finally i had the opportunity to meet Glenn Block.
Glenn is a PM for the new Managed Extensibility Framework in .NET 4
we have spoke of a few aspect related to the MEF technology,
also i cannot cover all the issues spoken in this post, i would like to
note one of Glenn comment about classic MEF scenario that exceed the scope of the IoC world.
the scenario is speaking about having plug-ins that may have their own
dependencies which your application doesn’t aware of.
this case is not the classic IoC scenario because the IoC declaration
has no information about the dependencies of the dependencies
(the second level of abstraction).
so in this case dependencies declaration may not fit, and other
discovery method should be considered.