Its been almost a year since .NET 4 was released (12 April 2010, so about 11 months). Microsoft introduces a lot of new features but there maybe something you find is missing. Specify what you want to be included in 4.5 (or if they skip to 5.0).
What I would like are:
A namespace for IMAPI (Image Mastering API) for burning cds.
A namespace for Zip, etc.
XNA included in .NET framework under a System.XNA namespace.