I've tried both your suggestions. Auto-playlist is kind of half-way solution, though. On the other hand, recently added files through Tag Manager is almost precisely what I was looking for. Only two small things to make it perfect. Firstly, make it accessible more easily and secondly add these top three columns with genre-artist-album as you can have them in main window. But still it's really usable for me this way as well.
I still think it would be powerful to have an option to bookmark filters in Music Library as I explained in my first post, though.
Thanks!