Why you can't search for tracks?
Just type the name of the track to the search bar (maybe you need to set it up to search in all playlists first: click on the search symbol --> Search in --> All playlists).
The results will be listed in a new playlist (not DarkOne behaviour but foobar2000 behaviour).
You could also easily search for artists:
single click in the playlist view and type-in the name of the artist.
Another search functionality:
Ctrl+F (will open an extra window with the playlist search)
Or the media library search with the ability to create auto-playlists:
Menu Library --> Search
Or use the filters or the album list or...or...or...
What do you mean with "difficult to scan albums"?
Replaygain scan? Scan in the media library (which isn't difficult, but automatic...)
Btw. DarkOne doesn't changes foobar2000's behaviour and doesn't limits its functionality in any way - except that it is totally made for edit (and of course listen to) the now playing file.
All who made statements about these "terrible skins" should probably TRY it first

Of course there might be some problems in its usage, because it is done to suit
my needs, but i at least try to answer every question and try to help with any problem the user may have when using DarkOne (on deviantart or the german foobar-users Forum and of course with the user guide shipped with DarkOne).