It's really a shame what happened to wildfire (and the ranged in general but that's another story). Back in HW it was one of the hardest hitting skills in the game at that time. People geeked out over their wildfire numbers all the time like people talk about their midare crits now. That's what happens when you have potency creep over the years, and some skills don't keep up.
What happened back then was many players complained that too much of machinist damage was tied to wildfire, and it was stressful because if you messed up it hurt your dps really badly. In order to appease those players and make the job more accessible they shifted more of its damage to the 'easy' parts of its rotation and cut down wildfire, to the detriment of the veteran machinist players.