And then let me get in my two cents.
I use cog as a player for temporary playlists. Usually audiobooks, that I don't need lined up in a library, but can load as needed. Sometimes I use it for listening through audio files with interviews and edited sound clips. What I like about cog is, that it is lightweight, it opens instantly. What I want it to be is something different than iTunes, which I use for my music.
Regarding the preference pane, I don't mind the split pages. I usually leave it alone (Do you guys change stuff often?) and I think it would be confusing if they were all in the same page.
Even when Cog grows up and becomes an extendable demon, that can make my coffee with the right plugin, I think I will leave it alone. I like that it is small, but at the same time I like the dream of being able to add just that little feature, that not so many people would want. When I first got Firefox I thought 'extensions, oh well', and moved on happy with browser, that could browse. Maybe the same will happen with Cog, someone makes a plugin, that I didn't know I needed.