I've seen the new trait you've added, and the other changes that you have undertaken. Unfortunately, I am not really impressed with the changes, and I think you would also not be fully satisfied either. Since you have the ambition to rework the traits a bit, I'd like to share my thoughts about the traits. But my thoughts are bit too unorganized, I'll just go through my thinking process with you.
Introduction: I mainly have a problem with the Expansive trait, and it should definitely be reworked. The problem is for instance; a Legislator+Charismatic leader will be expand quite effectively and would benefit much from expanding, however a leader with Expansionist+Imperialistic wouldn't benefit from expansion at all.
Ok, so what kind of benefits could the Expansionist leader have?
a) Easier to acquire unclaimed territory: Faster Settler production - this is already the case.
b) Easy to explore new territory: Faster production of Scouts; fast moving and more durable scouts: Therefore the scouts might start with Woodsman I, Guerilla I, better Visibility and/or Speed.
By the way, I'd tweak the unit upgrade tree so that: Scout -> (Early Explorer) -> Explorer and Skirmisher -> Light Infantry, so that there is a clear distinction between scouts and fighting units.
c) Expansionist leader should benefit from having many small cities, overseas territories and colonies - whether this expansion is peaceful or not. Therefore, the maintenance costs from Distance to Palace and/or Number of Cities could be reduced, or the cities might provide initial resources which (something better than +1
)
Ok, now let's have a look at other traits, which influence the expansion/military policies:
Imperialistic:
Impreialistic trait seems to be modeled after the Roman Empire's expansion policies. Shiny armies, magnificent monuments, glorious (military) leaders... And the current Imperialistic trait reflects those features well. I think the imperialistic trait is good enough but the new wonder production bonus is also fine, since it encourages you to build magnificent wonders in your magnificent empire. The problem with this trait is, that it does not really encourage you to go and invade new lands. I personally build those barracks, sit back and enjoy the early +1 happiness. I don't bother going and invading new territory and accept battles on my own lands to get the maximum out of the Great General bonus. Therefore, I have a few proposals:
a) +100% GG emergence outside cultural borders. This can be done by comibinig +100% GG emergence with -100% GG emergence in own territory.
b) Romans liked to enslave the people they defeated. Therefore, either higher chance of enslaving upon victory, or 2 Slaves are created instead of one. If you decide implement this, I would suggest you to deactivate +10% wonder production.
c) Units start with pacification. It resembles high motivation of fighting the barbarians (as Romans did) or colonizing the native people (as Europeans did in the Age of Exploration)
Seafaring:
This is exactly how the expansionist trait look like! Normally, I don't want to build too many cities from early on, but if I am seafaring, I don't mind building many coastal cities, since those cities immediately start to pay for themselves. This trait is good enough, it encourages you to build fleets, boosts the maritime trade, I don't have any suggestions.
Militaristic:
There can be two possible interpretations of militaristic:
a) People under this leader simply enjoy waging battles, fight courageously and spiritedly.
b) This leader puts emphasis on building large, well-equipped and/or well trained armies, and he uses them.
Point a) seems very close to the case of a charismatic leader, because in both cases the soldiers fight motivated. So, I assume that b) is the case for a militaristic leader. I further assume that the militaristic leader will simply build the most solid army possible and wouldn't be that interested in asymmetric warfare or hit and run tactics. Therefore, the charge mounted, melee, gunpowder and armored units should get the experience bonus, and not the recon and ranged mounted units. (it was already the case, right?).
Charismatic:
In my opinion charismatic is actually better than militaristic, because after level 4 or so the the charismatic units are better, and the XP-bonus of charismatic applies to all types of units. But it is difficult to find a balance between charismatic and militaristic. For now, I'd let it stay as it is.
Protective:
This is also good as it is.
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Ok, and where does the Conqueror fits?
First of all, Conqueror can not be considered as a real trait. A leader becomes a conqueror, only if he conquers somewhere. Being a conqueror is a possible result of following expansive/imperialistic and militaristic policy. So I already dislike the idea to be honest.
Also, boosting the cavalry units won't help you much when conquering cities. If you insist on Conqueror as a trait, then I'd propose you giving City Raider to melee and gunpowder units, and leave the Charge Mounted unit bonuses to the Militaristic trait. Conqueror should also give siege units a bonus.