In my current game, my traits at the moment are: Industrious I, Philosophical I, Seafaring I, Greedy I, Ancient Way of the Wild. I've complex traits on and pure traits off; according to the pedia as far as I can tell, there doesn't seem to be any impact of those on base cost of units or production speed modifiers for traders, but it is entirely possible that the pedia simply wasn't updated at some point.