You may consider revising some of the middle strength rankings some traits moved up there because they are stronger than it seems at first glance. Protective is now the same way.
Currently, the divisions are:
Strongest:
Financial
Philosophical
Medium:
Spiritual
Aggressive
Creative
Expansive
Industrious
Organized
Charismatic
Imperialistic
Weak:
Protective
According to some of your own criteria, a better division would probably be:
Strongest:
Financial
Philosophical
Medium:
Spiritual
Creative
Industrious
Organized
Charismatic
Weak:
Aggressive
Expansive
Imperialistic
Protective
Ill attempt to give some reasons for this below.
First, a side note on Creative: while it is most useful in the early game, the free culture is useful whenever you are taking enemy cities, when all cultural buildings are destroyed. Granted that you can use an Artist specialist from Caste System to expand borders, you dont always want to be in Caste System. Creative allows you to work on other initial builds in captured cities without having to focus on culture first.
Now, why should Aggressive, Expansive, and Imperialistic be moved down with Protective?
Here are some comments from your guides:
Regarding Imperialistic:
I originally included it in the Weak category, but now feel it belongs in Mediumif its used properly.
This indicates that proper use is essential to a traits rating. Given this, the comments on Protective:
The problem with the Protective trait is that its largely defensive in nature. (. . .) In many ways, the Protective trait seems to have been added more to benefit the AI than the human player. The AI prefers to play defensively for the most part, so Protective suits its programming.
are enlightening. Clearly, the AI does not use the trait well but does it follow that a human player should emulate the AIs use of a trait? By that measure, none of the traits are strong.
The key is in this, from the Stack o Doom guide:
While I have listed siege units as optional, in many cases they should be considered essential.
In the very early game, however, when cities cultural defenses are quite low (usually 20% at best), siege units are often not required to capture cities. A +20% defensive bonus can be readily overcome provided you have enough attacking units with sufficient offensive promotions, and youre willing to lose some of your units. Even when attacking a city with a +60% bonus (such as a holy city), you can overcome its defenders with sheer numbers; usually a 3-to-1 or 4-to-1 ratio of attackers to defenders will be required in that scenario.
As the classical era of the game draws to a close, however, cities cultural defenses will rise to 40% or higher, and several cities may be defended with walls and even castles. Also, your opponent may build the Chichen Itza world wonder, which boosts the defense of all cities in that civilization by 25%. Longbowmen, the strongest medieval-era defensive unit, also begin to appear. Under these circumstances, siege units go from being useful to being absolutely required.
Since siege units soon become the primary offensive weapon of the game, neither Aggressive nor Protective plays a direct role in offensive action Aggressives Melee troops are more often than not City Raiders, which is available without the free C1 Promotion. After the Siege Units are done, the free C1 doesn't make that much difference.
In essence, the only time Aggressives free promotion makes a large, direct difference is in the extremely early game, before the advent of siege weapons.
Protective can make an effective use of the Drill Promotions (with Longbows/Crossbows before Gunpowder) because Siege Units are used to take cities and damage units. Piece of Mind makes the point that Protective is the only trait that makes Drill 4 feasible, and that Drill 4 is an excellent promotion, in this thread:
http://forums.civfanatics.com/showthread.php?t=307430&highlight=Protective+Underrated&page=7
Given, again, that Siege Units do most of the work, units with First Strikes can be better and more profitable, XP/Great General points wise for cleaning up.
Aggressive actually becomes useful mainly for opening up some specialized promotions which drill does not. You mention under Imperialistic that:
You dont have to play as a warmonger with the Aggressive trait; you could leverage it to build a strong army and military infrastructure (the cheap barracks and drydocks count towards your power rating, after all) so youre left alone to build.
The same applies to early game Protective, with their cheap walls and castles. The question is
when it happens. The part of the game where Protective builds Walls and Archers is the part of the game where Aggressive has its potentially largest impact.
After Siege and particularly after gunpowder, the situation reverses itself. Protective becomes very effective thanks to gunpowder units with extremely quick access to Drill 4. Protective also has a solid if potentially short-lived economic boost in quick castles.
Which does not mean that Protective should be moved up to medium strength. Rather, Aggressive has gotten a higher rating than it deserves.
Likewise, Imperialistic and Expansive, which a person will only realize as being useful after taking more than a first glance.
Expansive gives you cheap Granaries and workers in the early game, cheap Harbors in the midgame, and better resistance to all the unhealthy buildings in the end game. However, it wanders somewhat from benefit to benefit; each one fades out as another takes its place. Compared to a trait like Industrious or Spiritual (Spiritual starts applying as soon as a religion spreads to you), Expansive doesnt have quite enough long-term Oomph. You might get the granary cheaper, but after theyre built, another trait uses Slavery to the exact same or better (Charismatic) effect.
Imperialistic allows for rapid expansion, then provides for better warmongering once theres no more room for Settlers. There's two bonuses, but rarely room for both at the same time.
Neither Protective, Aggressive, nor Imperialistic is as strong in war as the only trait which directly boosts siege units (and every other military unit in the game) by lowering the promotion XP requirements Charismatic. These traits therefore should not be ranked as highly as Charismatic. They belong in the weak category with Expansive. Not because they are worthless or useless, but because they are a collection of small or specialized bonuses rather than general or sweeping bonuses.