Here are some suggestions to help improve the 'less useful' traits. These are mainly 'icing on the cake' changes, but they do help round out the traits and help them to compete much better with the others. In the case of creative, it turns the trait from being an 'early game expansion-only' trait to one that will last the whole game and is especially useful for cultural victories.
Creative - artist specialists give 4 GPP instead of 3. This means 25 turns for your first artist instead of 34. 13 turns if you are Creative + Philisophical (apparently no leaders are, though). This obviously gives a large boost for anyone aiming for a cultural victory. This means in the time that it takes a non-cultural civ to get 6 GA via specialists alone, you will have gotten 7. This also gives you much more flexibility if you just need to get 1 or 2 artists, you don't have to spend as long using the artist specialists but can swap over to something else like scientists.
Expansive - +1 food from city centre. This helps to make less viable areas (lots of jungle/desert) easier to work as you've got more of a safety net available and helps your cities to grow faster. It also means that late in the game you could end up with an extra 1 pop in a particular city that another non-expansive civ may otherwise not get. Possibly this could be bumped up to +2 in city centre when an appropriate technology has been researched 1/2 way through the game - civil service or education? I think Biology is a bit late, but maybe others would prefer that.
Organised - either +1 hammer from city centre, or possibly +1 hammer from engineers or +1 GPP from engineers, hard to say. This goes along with the idea that organised civilizations are better able to work efficiently and organise (well duh) themselves when it comes to public construction efforts. While another civ might be bumbling around with the blueprints, the organised civ has already started construction on the foundations. +1 hammer from city centre means they always get the bonus, but the bonus never improves. Granting +1 from engineer is similar for most of the game - for a long time you can only have 1 engineer specialist with a forge. Later in the game you start to benefit from this more as more engineer spots become available. Alternatively, the 1 extra GPP would help mean that this civ will get more GEs than most others (if they try), however I'm not really sure if this belongs with Organised as its more of an Industrial type bonus. To be clear - I am suggesting only 1 of these 3 bonuses be added, but I am unsure as to which is the best path to be taken for this one.
Spiritual - +1 GPP per priest. This simply lets you get your prophets out quicker - you can either focus on getting lots of them for multiple religions/shrines, or get lots of them for the techs they give out, or simply use it to get the first 1 or 2 quicker and then swap to something more useful like scientists or whatever.