I deliberately put this thread into the general forums because i don't think it belongs in suggestions. Traders materials are currently too limited. they don't carry middle to end game resources like chalk (or very very rarely) they don't carry enough resources to support middle to end game colonies they carry the wrong resources for a starting colony (who needs beer, iron ingots or opium on day 10) So the only points i use traders for is the rare painting...since i need about 12 paintings for all my bunkhouses the overall need ceases to exists quite fast. Most of the time i have a trader coming in he is already leaving again because other things were more important...so for me a trader is one of the most useless things in the game (well apart from planting shrubbery and grass)
They're pretty important for their wood on (near) treeless maps like desert and steppe. Lacquer can be useful if you didn't get any beetles. I like buying raw materials like clay cubes or sand too, so my workshops can make those into bricks/bottles to sell to the next caravan - those tend to be my early trade goods.
Grumbled long ago about their trading decisions. Had one map completely stuck with no chalk - or at least I had one non-mineable surface node with not enough to make 4 steel ingots for the crusher (my other way to get chalk). Ended the game in the end as all the mines were as deep as they could go and still nothing. Traders need to have a rich variety of mid game items in addition to basics. Be nice if the Foreign Office Ore traders had chalk or steel ingots.
Would also like if cash crops were made non-pointless. Their problem is you need at least one dedicated overseer slot versus just selling off some of the surplus that accumulates anyway.