Anecdotal evidence is the least reliable, but personally I haven't found fire to be all that useful. It's never more than an annoyance (to me) when used on my ship, unless there's a lot ... and then, it's like "why didn't they just shoot me?"
As for when I'm using the fire ... I've never really had much results with that. Emptying whole clips from the flamer seems to distract the enemy for a few moments, maybe, but again- why distract when I could just roll a Gatling and strip their armor, or use a Banshee and do fire damage plus destroy components?
I'm not necessarily saying I want to see fire buffed — far from it — but I also feel like it's sort of a sideshow right now. Of course, that has more to do with the current ascendancy of direct damage over disable builds.