I know NS is always looking out for suggestions so here's some I came up with.
-Never ending threads. Threads that assimilate all the pages together into one, but with some clear divider as you scroll down that tells you the page. Would make it a hell of a lot easier to search through threads via ctrl-F. This could work by either loading the next one as you scrolled to the bottom, or some sort of "view all" option like online shopping.
-Verified seller checkmark. Once you sell a certain amount of items with certain positive ratings, you become verified. Not completely necessary, but it would be nice for us sellers/traders to be more "officially" recognized and would help our sale threads look more attractive. I thought of this after seeing nyles.'s thread today and thinking that he always hooks it up in his sales.
-Sort by "new" option for threads. Something I've already stated, but would be especially useful for sell/trade
Again, just ideas here. Throw in some feedback and/or your own ideas