Modified ModelState to only ever be created on the ActionContext and then plumbed/exposed it on ViewData and Controller. This will enable: ActionFilterContext's will have access to ModelState via its ActionContext member, allow HTMLHelpers to access ModelState via ViewData, and unify the locations of "source" model state. In the old world we used to copy/replace/instantiate new model state all over unnecessarily.
Andrew Peters
Ryan Nowak
Yishai Galatzer
N. Taylor Mullen
David Fowler