Update : Added a new blog post with a code fix of this issue – “Navigation hierarchies and key filters with slide library : Code Fix“
Some month ago I encountered with a problem of using Navigation Hierarchies and Key Filters with Slides Library. I was added the Managed Matadata field to my slides library and turned on the  Navigation Hierarchies and Key Filters on the Library Settings page and nothing happened. But the same sequence of actions works with Document Library.
In SharePoint’s logs I had found following record:
MetadataNavigationContext Page_InitComplete: No XsltListViewWebPart was found on this page[…]. Â Hiding key filters and downgrading tree functionality to legacy ListViewWebPart(v3) level for this list. Â Â 265d58e5-27f4-40a3-8ab5-4b80013588ab
I have placed my problem to MSDN SharePoint 2010 Forum : http://social.msdn.microsoft.com/Forums/en/sharepoint2010general/thread/a7970e71-6895-4751-a2be-d9043c9ddd6c but it did not help me =)
We have found the solution of this problem and I will try share it to you.
Let’s open default view page of the slide library in the SharePoint Designed 2010.
And what we see? Default view page which was generated by default slide library template contains old ListViewWebPart. We need to replace this web part on the new XsltListViewWebPart .
I propose you the way to do it without using any custom utils except SharePoint web UI.
- Open the Slide Library and click Site Actions\Edit Page.

- Choose a web part and click Edit Web Part.

- Change the Selected View property from <Current view> to <Summary view>. And click OK but  do not click Apply.

- Click OK in the  popup window.

- Click the name of your library into the left navigation panel.
Now you can open the view in the SharePoint Designer 2010 and see that web part was changed.
Navigation Hierarchies and Key Filters also working.
P.S. Thank to Aliaksandr Haurylik