Reply to Yigal,
One of the major benefits of using D is
that you get the convinience of Ruby/Python and the speed of a
natively compiled language. using D on .net removes this very important
benefit. All the things you mentioned above can be acomplished already
with C# or any other .net language (visual C++) with the support of MS
and all the tools already available for it. the most important benefit of D
is the fact that it's natively compiled. remove that and you'll get a
roughly equivalent language to C#.
at least that's my opinion.
On advantage of D for .NET would be that is would allow for using existing
code to be hooked into .NET apps. I don't think that writing new apps in
D for .NET would be wise but bringing existing apps into .net would be good.
OTOH there might be a niche for D as an unsafe .NET language.