the DB should understand limited hierarchies for boxed sets, 2-disc and multi-sided DVDs, and TV series.
You're confusing things based on a very small view. The database does, in fact, understand relationships between most of these concepts, however the UI does not have functionality to use that information to build a hierarchical representation. Since the database understands the relationships, you can use the search which will give you some of what you're looking for. These are the current features.
If you search the forum, you will see multiple discussions about how to design and implement such hierarchical views of the media, but this feature is not available currently.
Also - I'm finding filtering under 08.10 does't work.
This is simply not true. I use the filters and searches every day.
Before I posted all this, I tagged a disc as 'Drama' and 'TV Show' and did an Amazon metadata lookup in Media Sync.
In writing this post I've just discovered that filtering on Genre now works if I have a user selected in the filter, rather than just 'Public', but why that should make a difference is beyond me and it doesn't affect filtering on 'TV Show'.
If you get no results when you expect results, you probably have not tagged the media properly. For 'TV Show' vs 'Movie' filtering, you must set the "Media sub-type" drop-down in the "media file sync" section of the web admin. This is a completely separate setting from the "Attributes" section. Make sure you hit the "Save" button to save your changes.
Beware - when you do Amazon or IMDB metadata lookups, you may replace any tags you have manually applied. There is a radio button to choose the behavior just before you accept the new tags, I believe. The media you think is 'Drama' may be something different to Amazon or IMDB, or the lookup may not provide a genre at all. I'd suggest using IMDB instead of Amazon - the data is much cleaner, and I know for a fact that genres are included.
The fact that things work if you have a user selected means that the media belongs to a specific user. Read about file structure in the FAQ - you probably have a storage device owned by the wrong user or have put the media under a user's directory.http://wiki.linuxmce.org/index.php/FAQ#How_are_media_files_organized.3F