The supported metadata does seem to be more aligned with audio than video. I agree, more is better. When you look at what's supported by .nfo files, you can see lots of metadata that would be useful (I bolded some that I'd prefer to see ASAP for movies):
Movies
<movie>
<title>Who knows</title>
<originaltitle>Who knows for real</originaltitle>
<sorttitle>Who knows 1</sorttitle>
<set>Who knows trilogy</set>
<rating>6.100000</rating>
<year>2008</year>
<top250>0</top250>
<votes>50</votes>
<outline>A look at the role of the Buckeye State in the 2004 Presidential Election.</outline>
<plot>A look at the role of the Buckeye State in the 2004 Presidential Election.</plot>
<tagline></tagline>
<runtime>90 min</runtime>
<thumb>http://ia.ec.imdb.com/media/imdb/01/I/25/65/31/10f.jpg</thumb>
<mpaa>Not available</mpaa>
<playcount>0</playcount>
<watched>false</watched>
<id>tt0432337</id>
<filenameandpath>c:\Dummy_Movie_Files\Movies\...So Goes The Nation.avi</filenameandpath>
<trailer></trailer>
<genre></genre>
<credits></credits>
<fileinfo>
<streamdetails>
<video>
<codec>h264</codec>
<aspect>2.35</aspect>
<width>1920</width>
<height>816</height>
</video>
<audio>
<codec>ac3</codec>
<language>eng</language>
<channels>6</channels>
</audio>
<audio>
<codec>ac3</codec>
<language>spa</language>
<channels>2</channels>
</audio>
<subtitle>
<language>spa</language>
</subtitle>
</streamdetails>
</fileinfo>
<director>Adam Del Deo</director>
<actor>
<name>Paul Begala</name>
<role>Himself</role>
</actor>
<actor>
<name>George W. Bush</name>
<role>Himself</role>
</actor>
<actor>
<name>Mary Beth Cahill</name>
<role>Herself</role>
</actor>
<actor>
<name>Ed Gillespie</name>
<role>Himself</role>
</actor>
<actor>
<name>John Kerry</name>
<role>Himself</role>
</actor>
</movie>
TV Shows
<tvshow>
<title>MythBusters</title>
<rating>9.300001</rating>
<year>0</year>
<top250>0</top250>
<season>-1</season>
<episode>143</episode>
<displayseason>-1</displayseason>
<displayepisode>-1</displayepisode>
<votes></votes>
<outline></outline>
<plot>So exactly how hard is it to find a needle in a haystack, anyway? And can water dripping on your forehead really drive you nuts? Those are the kinds of questions, myths and urban legends that are put to the test in this humorous series to find out which ones hold water (and keep it from dripping on your forehead and driving you insane).</plot>
<tagline></tagline>
<runtime></runtime>
<thumb>http://thetvdb.com/banners/graphical/73388-g3.jpg</thumb>
<thumb>http://thetvdb.com/banners/graphical/73388-g2.jpg</thumb>
<thumb type="season" season="1">http://thetvdb.com/banners/seasons/73388-1.jpg</thumb>
<thumb type="season" season="0">http://thetvdb.com/banners/seasons/73388-0.jpg</thumb>
<thumb type="season" season="2">http://thetvdb.com/banners/seasons/73388-2.jpg</thumb>
<thumb type="season" season="-1">http://thetvdb.com/banners/posters/73388-1.jpg</thumb>
<fanart url="http://thetvdb.com/banners/">
<thumb dim="1920x1080" colors="|183,185,161|51,51,51|206,205,185|" preview="_cache/fanart/original/73388-6.jpg">fanart/original/73388-6.jpg</thumb>
<thumb dim="1280x720" colors="|255,255,240|101,141,117|129,132,123|" preview="_cache/fanart/original/73388-1.jpg">fanart/original/73388-1.jpg</thumb>
</fanart>
<mpaa>TV-PG</mpaa>
<playcount>0</playcount>
<lastplayed></lastplayed>
<episodeguide>
<url cache="73388.xml">http://www.thetvdb.com/api/1D62F2F90030C444/series/73388/all/en.zip</url>
</episodeguide>
<id>73388</id>
<genre>Reality</genre>
<set></set>
<credits></credits>
<director></director>
<premiered>2003-01-23</premiered>
<status></status>
<code></code>
<aired></aired>
<studio>Discovery</studio>
<trailer></trailer>
<actor>
<name>Robert Lee</name>
<role>USA Narrator</role>
<thumb></thumb>
</actor>
<actor>
<name>Adam Savage</name>
<role></role>
<thumb></thumb>
</actor>
<artist></artist>
</tvshow>
TV episodes
<episodedetails>
<title>My TV Episode</title>
<rating>10.00</rating>
<season>2</season>
<episode>1</episode>
<plot>he best episode in the world</plot>
<thumb>http://thetvdb.com/banners/episodes/164981/2528821.jpg</thumb>
<playcount>0</playcount>
<lastplayed></lastplayed>
<credits>Writer</credits>
<director>Mr. Vision</director>
<aired>2000-12-31</aired>
<premiered>2010-09-24</premiered>
<studio>Production studio or channel</studio>
<mpaa>MPAA certification</mpaa>
<epbookmark>200</epbookmark> <!-- For media files containing multiple episodes,
where value is the time where the next episode begins in seconds -->
<displayseason>3</displayseason> <!-- For TV show specials, determines how the episode is sorted in the series -->
<displayepisode>4096</displayepisode>
<actor>
<name>Little Suzie</name>
<role>Pole Jumper/Dancer</role>
</actor>
<fileinfo>
<streamdetails>
<audio>
<channels>6</channels>
<codec>ac3</codec>
</audio>
<video>
<aspect>1.778</aspect>
<codec>h264</codec>
<durationinseconds>587</durationinseconds>
<height>720</height>
<language>eng</language>
<longlanguage>English</longlanguage>
<scantype>Progressive</scantype>
<width>1280</width>
</video>
</streamdetails>
</fileinfo>
</episodedetails>
Even music videos
<musicvideo>
<title>Bestsongintheworld</title>
<artist>Bestartistintheworld</artist>
<album>Me</album>
<genre>Pop</genre>
<runtime>3:20</runtime>
<plot>Scantly clad women hoing about</plot>
<year>2000</year>
<director>and I</director>
<studio>Ego prod.</studio>
</musicvideo>