Financial is probably the easiest trait for civ3 players to understand, since it's a lot like Republic in civ3. That and creative. I suspect we'll soon see lots of threads complaining about how the traits are unbalanced until people get good at maximizing the other traits.
Philosophical - It still makes me uneasy sacrificing growth by pulling people off the land to specialize. And getting wonders is very hard without prebuilds.
Industrious - Doesn't it hurt to have this trait and not have stone or marble? And actually aiming for an ancient age wonder goes against everything I learned in Civ3 about wonder addiction.
Aggressive - You'd think that this would be straightforward, but since it's harder to make an early rush, and less profitable to capture enemy territory, you have to adapt to new combat doctrines, such as pillaging and containment, which make warfare seem like a total waste before you have catapults and overwhelming numerical superiority.
Expansive - Thanks but no thanks, I have enough food resourcs as it is, and not enough luxuries. I suspect that the best use for this trait is that the extra health lets you trade away your food resources for luxuries. Maybe it's good for cultural victories where you want a few giant cities and the culture slider takes care of your happiness.
Spiritual - This will become useful as soon as we all get a feel for min/maxing civic settings turn by turn. For example, switching in and out of Organized religion depending on how many buildings are under construction vs. how much you're paying for civics, or going to Hereditary rule for a few turns in order to turn down culture and max out science to wn the race to a crucial tech.
Organized - This is worthless if you're running cheap civics. Depends greatly on your playing style, but certain combinations could be both useful nad expensive. Also it's the only way to cotrol costs with expensive civics.
Note that I'm not saying these traits aren't good, it's just that they're narrower and deeper than financial, and will probably take more praciitce before they're as useful.