I must say that I like inkscape-default quite a bit, and would hate to
see it go. (I use the first 30 or so colors a lot, the rest I hardly
ever use)

So lets keep the first 30 in the default set . its the bloat that makes navigating palettes un-fun. trimming it would be great. keeping it as default is fine too.

And before we shoot any of the "geographic" ones, we better make sure
none of OpenStreetMaps et al. guys will be after us with torches and
pitchforks :)

which ones in particular? topographic?

I'm not opposed to leaving some in there as much as I am in favor of cleaning what is there up a little . for example khaki could do with a massive trim down to some primary hues, it would make quite a nice palette if it werent so huege (pun intended)