Truth be told, our role changes as well depending on what you are running and your spec. If I am running a MM WZ generally my role is take people out in order to buy time to win the match. Consider that in Huttball or Voidstar you can take someone out of the game for up to 30 seconds or even more, that is a huge advantage to your team. In Civil War I plant myself on a ramp and I am the node killer, and in War Games I am a runner, I go from base to base taking out targets. I will cycle my targets to get the lowest health bars out not because I want to rack up a million kills, but you are more apt to win when 4 people are waiting to respawn instead of 1. If I am running ENG my job is most likely to DOT away. Weaken the enemy and perhaps allow another sniper or DPS to take out targets. I will cycle targets for the opposite reason, pick the healthiest and weaken them. Lethality to me is just run and gun, keep a target occupied, generally a good healer, and bug the heck out of them. Snare is my friend in Leth.
For a Flash Point, we know we are the burners, its just a matter of how to do it.