Based on people's analysis, I'm leaning towards the purple action being something that you MAY spend a force to do ON TOP OF your normal action. Another way of putting it would be: Vader may treat all of his actions on his action bar as being purple.
This would mean that the jedi fighter would be able to exchange a force token for an evade token on top of some other action (probably a focus). This makes it a strong evasion tank.
I'm not sure how many people will use the base craft without the stat-adjusting configuration. The stat adjustments bring it closer to being an X-wing. The difference being that it can boost or barrel roll without doing anything fancy. I wonder why the rebels didn't just get as many of these as they could...