We are planning to introduce the FocusVisualStyle (as in WPF) property for all controls so that managing this will be easier. We have had some contradicting feedback as to whether and where there should be focus elements. It seems that this should be easy enough to change.
As for the slider - I checked the code and it in fact is using the Focused and Unfocused states. It turned out that the metadata attributes that describe this for Blend are not there. This has been fixed and should be available for the SP.
If you create the states in Blend, even though it does not know that they are there, they should be used at runtime.
Thank you for your feedback once again.
Your Telerik Points have been updated.
All the best,
the Telerik team