At the moment when creating a new Civilization our options for Traits are fairly limited. It may /seem/ like there are many traits to choose from, especially on the positive side, but I find quite a few of the things I would be looking for to create/distinguish a fantasy civilization are nowhere to be found.
That being said, we're /definitely/ in need of far more negative traits than the scant 5 we currently have.
As for positive traits, I'd like to see some of the actual traits given to the canon Kingdoms and Empires, such as Seafaring, Great Farmers, etc.
I think that some of the traits should have two bonuses which work together, a starting bonus and a persistent bonus, as some of the traits right now say give you access to a late-game power/tech, but do little else.
It doesn't make any sense to have a civilization start off with a bonus to a resource they never end up finding in game, so starting traits should provide a starting bonus as well as a persistent in-game bonus, this way you don't have to worry about gambling between long and short-term.
Master Horsemen: Wild Horses Located near Starting Location. Cavalry units receive +2 bonus to speed, cost 10% less.
Seafaring: Beach located near starting location. Naval units receive +2 bonus to speed, cost 10% less.
Agrarian: Fertile Land located near starting location. 10% bonus to food production.
Woodsmen: Located near Old Growth Forst, +50% defense bonus when within woods.
Master Archers: Start with Archery Technology, Artillery Units cost 10% less.
Nomadic: Cities cost less to found, receive compounding penalty to productivity every few turns, receive large monetary bonus when disbanding.
Some of the existing Talents such as Master Smiths have an advantage that it seems it would take near the end of the game to receive, and I think it'd make more sense if say, armor/weapons had a reduced Materials/Iron/Gold cost than the current stats.
As for negative traits, I'd like to see things like:
Cursed: 10% penalty to food production.
Primitive: Can't harvest Iron resources or create Forges and Iron equipment.
Poor: Half starting gold, and 10% penalty to maximum trade/gold per turn.
Cowardly: Morale penalty in combat, Sieges take less time to end.
Mercenary: Very likely to be betrayed by your own people. Your armies can be recruited like NPC's by the enemy.
These kinds of things would go a long way towards making each civilization stand out more. Imagine it Rohan was just a generic fantasy civilization, or that the Mirkwood Goblins didn't have spiders or woods anywhere nearby.