...What I realised when thinking about e.g. the system in GC2 was that a "passive modifier" doesn't make the game more fun even when it is hugely important and influential in the game. Take for example the Federalist modifier in GC2 giving you +20% (or was it +15%??) bonus to economy. Hugely important, but the game isn't really any more fun to play and you never really think about it.
What would be better is to always try and make something active out of the talents, so that the player can take action and DO something, affecting the game. For example, instead of having "Merchant"/"Commercial" mean +2 gold per turn or +2% economy/gold, it should give the sovereign the possibility to cash in a certain amount/percentage of gold (gained from an especially lucrative transaction), once or a few times during the game. This is more fun because it means you as a player can decide when you badly need more gold. Like, when you are out of gold you can use the ability to save your hard-pressed civ. Or when you need to urgently construct an expensive building you cash in the gold. Or maybe you are dreaming of buying/making that magical item but lack the money, and through your talent your dream comes true ...
I'm just wondering how we could work on turning these passive bonus suggestions into active abilities...
Going back to GalCiv2 for a moment, take your auto-exploring survey ship(s)... rather than passively giving you bonuses every other turn, perhaps they could collect the junk they find and you'd gain the bonuses when they landed on a planet? It would mean you choose where and when to cash in the bonus (allows for some planet specific and empire wide bonuses)
The same concept could be applied to adventuring and item discovery in elemental. Also, it would be interesting if adventuring traits allowed you to activate things in different ways. So with a hero collecting loot, they have to return to a city to drop it off... their traits could determine the result. (keep the cool items, sell them all, stash them in the city, give them to other heros...etc.)
With some of the production bonuses you could activate them and mark yourself as the foreman of a mine (+%) or whatever. Perhaps some of them should require you to be within either the city of your culture.
I suppose the question is how noticable are they? You only notice something if you see a change, some before and after. If you have a passive bonus from the start that is permenant, you've adjusted the difficulty setting but nothing else. Some things are easier, some things harder... but you don't really notice. If you have a reason to look at that attribute you would notice those passive bonuses... but you don't often have a reason.
In sins, the envoy passive bonuses you notice because you're looking for when they hit the level where you can start pacts. (although they're still not perfect, autocasting abilities become passive abilities and you forget about them... and end up bombing a world that your envoys are actively but automatically (and therefore passively - without user action) boosting the population growth/or health... as an annoying example)
One option would be for some traits to unlock event options, with an indicator to show which trait you're using. So:
necromancer trait could unlock some evil options to certain events. A plague would now have the normal save the people option as well as a 'study the plague' or 'raise plague zombies'.
Negotiator could have an option in trades to "use negotiating skills" to have a small boost to the value of your goods, Or "rip-off" gives you an item in the trade window of high value, but if you sell it you lower relations. (sell a penny as "The magic meeting charm" with a small chance of actually being the item you said it was if the other person is lucky)
Diplomatic would allow you to reach compromises more easily... in cases where a lot of your items have 0 value to the other faction and your shard is 1. They want your shards, nothing else is worth anything. They demand 1 shard. You "diplomatically negotiate" and they will now accept food and wood. (reduces the value of your shard, increasing the relative value of other items... as such is hard to use offensively. I.e. you can only target the item they are requesting to make them lose interest in it if it's valuble to you)
Wise could allow you to activate it to remove the penalty for an event... which would allow you to activate it and benefit from any gobal events. It's cost would have to scale with the likelyhood of mega-events... if you may not get a single huge event it should be cheap, if you're highly likely to get at least one event before the game is over then it should be expensive.
Gambler - activate to increase the RNG on events or items. So, activate it before attacking a dragon and be more likely to get amazing artifacts, or just a small pile of gold. Deactivate it and any "gambler" options in events is lost.
Not sure what's best to make you notice or think about traits... anything that encourages user actions... it doesn't mean losing the passive bonuses, just having each race have at least one or two active ones. Say, diplomatic and having some quest, they'd have a different start (looking for quest stuff) and would be harder to scam.
If "archery background" allowed you to build a free archery range (once or every 20 turns) and had a small bonus to archers under your command it would be a little more active and quite probably change your entire army to use more archers. It'd have an effect in the early game, but taper off as you could quite easily build lots of barracks in the late game. (unlike a flat reduction in archer cost, global bonus or a late-game effect like increasing the level cap of archers or allowing the research of adamantium arrows, which would all have different use curves.)
"archery background" or whatever could have lots of different potential active effects. In game battle commands like volley, the ability to upgrade/downgrade troops to archers (keeping their armour)... that could be quite interesting... if you lose your archers but have your knights left... give them bows, spend a turn training them and you have platemail archers with swords for close range. (lose the horses).
"Archer" as a trait may also change the loot you find... since you'd notice the dull brown, old and dusty bow that is actually a dull-wood bow of invisibility. Maybe the equivalent of having a second identify check when you find bows. Allows you to identify magical items that you wouldn't have noticed. Either that or simply increases the % chance to find bows. But I'd rather the items were there to begin with you just didn't notice.
Archer could allow you to station your sov in a city and research archery techs, so while your sov is in a city research points from that city are doubled, only towards archery or missile related techs.