I say this is unbiased, because I don't care either way what the official ruling will be. We get the rules and we make our decks to work within them. So given that and knowing that an eventual official ruling might change how I play, I still figure we need to be as objective as possible in figuring out the rules.
The logic:
Card Text: "
Enhance the Death Star dial. This enhancement cannot be targeted.
You may engage the Death Star dial as though it were a dark side objective (it is not an objective). If the dial has 10 or more damage, the light side wins the game."
Trench Run specifically tells us that the Death Star dial meets the requirements to engage it as though it were an objective.
An "Objective" is a card type, NOT a trait.
An "Engaged Objective" is not refering to a card and is also NOT a trait. It's referring to anything that has met the requirements to be engaged as an objective and is being attacked. This is given by the attacking player and it lasts until the end of that engagement.
In Conclusion:
If a card says "Objective" alone it's referring to an objective card.
If a card says "Engaged Objective" it's referring to the target of the current engagement.
Wookie Navigator Ruling
The card reads: "
After this unit survives an engagement as an attacker, you may engage this same (engaged) objective an additional time this phase."
The trigger to the effect is the word "After", so the moment Wookie Navigator is considered to have "Survived", the over-ruling effect is now in play before the engagement where the Death Star dial is still considered the "Engaged Objective" is over.
In the second part of the card the word "same" implies the redundant word "(engaged)" as only the objective that was currenly engaged would be considered the "same". The word "objective" on this card is not referring to a card and its card type.
In Conclusion:
You may use Wookie Navigator to attack the Death Star dial twice.
The balance of Trench Run is in the fact that a person using it either has to focus all of their attacks on one place to be effective… ether separate attacks on original objectives or all on the Death Star Dial. Either the DS defends like normal or they defend with all of their people in one place. The LS picking away at the Death Star dial with secondary attacks can be seen just as if they were doing the same to a 2nd and 3rd regular objective.
If the DS can't shut down one card by prioritizing their attacks on the Wookie Navigator or event/fate cards, then they wouldn't be able to take out the other units doing damage in the first place let alone their "clones" in the second attack.
I used to feel like I lost even when I won with the LS simply because it would get close to 12 on the dial. Now I realize that it's as valid a win as the DS using effects to turn the dial up or doing direct objective damage like with the game ending Superlaser Blast on a third/fourth objective. The dial is a timer for the DS winning, and each damage needed to win is the timer counting down till the LS wins. If the DS can't control the game enough to defend a single objective from a 10 damage timer of 1-3 damage, then hopefully they can earn their 1-3 damage first by destroying LS objectives.
The game comes down to seeing who can manipulate their unique "Win Timer" the best.