Great insight on what is coming ahead in WF 4.0!!! Kind of like the newer model with Activities inherently being treated as composite activities and WorkflowElement taking the role of "Activity" in WF 3.0 to execute the actual unit of work.
The re-hosting solution seems much simplified now.
I am quite excited with the prospects Oslo and "M" is going to bring about in WF 4.0. Declaring a domain model on language constructs which can be treated as activities underneath is quite exciting. This is going to bring text based workflows to forefront
something which was very challenging in WF 3.0.
The other thing I am equally excited about is the new activity designer on WPF. People who have tried tweaking activity designer on .NET 3.0 using GDI+ will understand the pain they had to go through to make just simple things work.