Just mentioning a "ressource" which was not mentioned before:
Troop positioning
I think that is rather essential and one of the most important things, especially in early game.
Why leave the FM in WH as Stark? Positioning (+cp)
Why move the FM out of Saltshore as Martell? Positioning (+castle)
Why not moving to the Reach in 1st round as Tyrell? Positioning.
Why take FF as Greyjoy (instead of staying in Pyke to CP)? Positioning (+castle). Well, it is rather interesting issue. But there are indeed some other options for opening and the value of positioning is also conservative...
Stark can choose either to CP in WH or move it to Karhold.
Martell can choose to CP in Saltshore.
Tyrell opening with taking the Reach is OK. At least not an obviously bad choice.
Greyjoy also has an option not to capture FF on turn 1. Instead, he can leave that ft in Pyke to continue CP or move it to Riverrun.
Of course, you can do alternative orders, but my main point is that the openings I mentioned (which are often played) are primarily good because of the troop positioning you reach with them. Everything else is a minor benefit compared to that.
For example, if you don't need a FM in WH (since Greyjoy does not attack you) the opening to move out the FM is actually quiet good (despite the fact that you are low on tokens for a round 2 clash), but if you have to fear gj aggression, having no troops in WH can totally cripple you and you have to hope for mustering (which also strengthens gj).
Hence, I personally don't move out of WH because of my weakened troop position if I did, not because I think it is essential to farm a single token in WH.
Troop positioning
I think that is rather essential and one of the most important things, especially in early game.
Why leave the FM in WH as Stark? Positioning (+cp)
Why move the FM out of Saltshore as Martell? Positioning (+castle)
Why not moving to the Reach in 1st round as Tyrell? Positioning.
Why take FF as Greyjoy (instead of staying in Pyke to CP)? Positioning (+castle). Well, it is rather interesting issue. But there are indeed some other options for opening and the value of positioning is also conservative...
Stark can choose either to CP in WH or move it to Karhold.
Martell can choose to CP in Saltshore.
Tyrell opening with taking the Reach is OK. At least not an obviously bad choice.
Greyjoy also has an option not to capture FF on turn 1. Instead, he can leave that ft in Pyke to continue CP or move it to Riverrun.
Of course, you can do alternative orders, but my main point is that the openings I mentioned (which are often played) are primarily good because of the troop positioning you reach with them. Everything else is a minor benefit compared to that.
For example, if you don't need a FM in WH (since Greyjoy does not attack you) the opening to move out the FM is actually quiet good (despite the fact that you are low on tokens for a round 2 clash), but if you have to fear gj aggression, having no troops in WH can totally cripple you and you have to hope for mustering (which also strengthens gj).
Hence, I personally don't move out of WH because of my weakened troop position if I did, not because I think it is essential to farm a single token in WH.