You made some good observations!
Part of the functionality you requested is being considered for implementation, such as...
- ability to view unread posts;
- highlighting the most active threads;
- filtering answered/unanswered threads.
As to the "mark all as read" - we're still researching whether most forum visitors need such functionality.
Currently there is a trend among forums to simplifying the interface by reducing features. As an example I want to point you to the newly redesigned Google Forums, where they cut some of the functionality they had in the previous version.
All the best,
the Telerik UX team
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