,ManipUni wrote

No improvements except ASP.net/HTML5. 

Can't agree. There's nice improvements in WPF. Support for static property binding, and a "new" pattern for surfacing property change events for static properties is welcome. The WeakEvent stuff is very nice, and should make using weak events much easier. INotifyDataErrorInfo is an important port from Silverlight. A bit low level, but I've wanted the new BindingExpression stuff for quite a while. The new methods on Dispatcher are minor, but they will vastly improve what calling code looks like. Finally, it's beyond time we have support for markup extensions for events. The last should make the MVVM pattern easier to use with events.

WCF, likewise, has some major new improvements. WebSocket support alone has me intereseted.

The changes for networking are also very welcome and important. HttpClient alone is worth being excited about, even if we've had variations on this available through CodePlex projects for a while.