I don't know anything about programming a distro, but I do have some suggestions to lighten some applications or give alternative applications that may reduce file size. One of them is already posted (CMUS - http://forum.slitaz.org/topic/cmus-default-music-player ).
It is a command line interface music player. It is fully functional.
I also recommend NAIM (http://naim.n.ml.org/).
If these products are used in conjunction with
SCREEN (http://www.gnu.org/software/screen/)
Resources can be freed up graphically even from alsa player and pidgin and used elsewhere, such as web browsing or graphics making.
I don't know how to get this to the proper channels to see if these changes are good ideas or bad ideas and if they can be implimented in the following release. I also think it would be a good idea to have firefox pre-loaded with flash install if possible. If that's not a thing linux can do I understand. I am just trying to help make the distro better and lighter.
Best wishes.