2. Playlists; this is already available in bit bucket.
The playlists are great but static, which is a disadvantage is some situations. For example:
1.) you want to filter games by system, genre and number of supported players and you have 40 systems, 30 genres and 4 players. So you need to setup 40 * 30 * 4 = 1200 playlists...each filter value adding to it will multiply the amount of work.
2.) you need to do alot of preparatory work before you can filter out games and can't do it impulsively
3.) everytime you update your romsets you have to edit all playlists and add/remove the new games
I would like to have something like a simple filter-menu. You press a button on the controller/keyboard and a menu pops up. With the Up and Down keys you can switch between menu items (number of players, genre, system, region/language, ...) and with the Left and Right keys you can step through the predefined values the metadb is using (1P, 2P, 3P, 4+P) (Platformer, Puzzle, Shooter, ...).
The filter will be used on top of the static filtering by checking the items of the collection/subcollection/playlist against the dynamic filter and the metaDB.
So you could easily filter out any games your not interested in at the moment in seconds. And you can do it all without keyboard and mouse. Such a menu would also be a good place for your search function by the way.