I am going to demonstrate while this map has distinct terrain advantages in favor of one faction. It has been my experience that this specific map is dominated by a singular faction during PvP for the simple reason that the map heavily favors their objectives. The faction which rules in Port Scion? The Guardians.
1. The Bridge:
The Bridge is pretty simple to hold for both factions. The singular advantage the Guardians have in this setting is the distance from Rez Pad A to Bridge B.
The distance is shorter by enough time to allow them to mass on the bridge much faster than the Defiants. At the same time, the choke point to prevent them from massing is much larger, so they have the ability to form a better offensive to take the bridge than do the Defiants.
As you can see in this simple diagram - the Guardians path is close to being a straight line. There are virtually no obstacles, and the 150% mounts easily pass through this area without getting caught on corners or having to weave through objectives.
This simply means the Guardians can "get there quicker", and you will always notice when a match starts that the number of guardians at the Bridge objective point is greater than Defiants right out of the gate.
Can this be overcome? Sure - with the right composition and organization, the Guardian's larger numbers and faster reinforcement can be defeated. It does, however, present a tangible advantage.
2. Idols / Planars:
These are simply entirely imbalanced as far as Defense and Access are considered. First we'll discuss the Southern objectives:
• The Defiants can be cut off from their southern planar via the Bridge which connects their rez pad to the Planar Capacitor.
• The Guardians Southern Idol of Planes is better defended as it is in a depression in the ground, which requires players get within 20m of the Idol to DPS, or they will be LoS'd - that is not the case for either of the Defiant Planar objectives. Neither of them are defended by a LoS mechanic which requires you must be closer than maximum range to attack the object.
As you can see with the above diagram - the choke point for these southern objectives prohibits a defense from the Rez Pad by the Defiants. In addition, the much more significant distance between the Rez Pad and the Point of Attack gives the Guardians an additional advantage when attacking the Southern Objective while it is being defended. This is one of the most significant advantages the Guardians have over the Defiants on this map.
Now we can discuss the Northern Objectives - where the Guardians still have a distinct advantage.
• It is at least 20-30% faster to reach and reinforce an assault on the Defiant Northern Capacitor than for a Defiant to reach the Guardian's Northern Idol when the Bridge is not controlled.
• When the Bridge is controlled, is dramatically easier for the Guardians to attack the northern objective. Defending the Northern Idol for the Defiants also leads to a battle at two locations, while the Guardians normally only have to defend a single point of attack since it is dramatically shorter.
The final obstacle is a matter of objective opinion and a matter of annoyance more than a significant advantage. The distance a Defiant must run to capture the Sourcestones. The map will show a very similar distance. The issue comes at the very end of the Defiant Sourcestone run. The long snaking pathway that leads up to the boss adds an additional few seconds to the run over the Guardians much more direct ramp that has less obstacles.