Just my point of view: .Net Application server: Definitely Yes! I start to look at JBOSS. I think that we should migrate it to .Net. Migrate and not convert because we can use .NET (attributes, codedom/emit, generics, generic aware reflection and app domain) to create more faster
and robust solution then JBOSS. But I think that JBOSS is good starting point, eventually several PhD's came out from that project and jboss already prove himself.
I don't think that Microsoft should do it alone. I think that MS with .Net community should do this immigration as open source initiative so both Microsoft and the community can gain benefits.
I don't think that Microsoft doesn't try to get a position in enterprise development. MS try to do it by investing in community, developers and so to penetrate enterprises from low level. Well, that might work (I'm not marketing genius ) but without competitive
tools to other vendors in the market I really don't see MS as leading force in enterprise development.