I'm working on a fanfic and I noticed that when it comes down to it fire bending can't really compete with other forms of bending past a certain point. Unless I've missed something then please feel free to enlighten me. However I'm discounting fire bending feats during Sozin's Comet as they had to rely on external stimuli to produce those feats. Thus I'm trying to find a way in which I can bring fire bending up to par with the other elements.

The way I see it, the main reason the Fire Nation is as big a threat as they were and were able to wage war on the scale that they did isn't because of the strength of their bending but rather the strength of their industry. They were able to produce weapons armor vehicles and ships at numbers and speeds that were frankly ridiculous. However when it comes to bending it seems to me that fire bending falls short.

At the lower levels of bending I believe that fire benders pose a higher danger than those of their Water/Earth/Air bending counterparts. However it's once we get into the higher levels of bending fire benders start seeing diminishing returns as masters of other elements  become literal forces of nature able to move islands throw mountains and create tidal waves. The only fire bending feats I'm aware of that equal those are during Sozin's Comet which I've already stated why I'm not counting. That's not even counting all the crazy shit that's possible with the other elements. Like you can use earth bending to become immortal somehow? Healing and blood bending with water bending. Straight up flight (not with air gliders but just straight up superman type flight) and whatever crazy shit yang chen can do(if you know, you know). Next to that lightning bending doesn't seem all that impressive.

I've thought about giving fire benders some form of energy bending minus the giant kaiju forms, but apparently energy bending is something else entirely, so I'm stumped. If anyone has any ideas please let me know.

How can firebending be made more of a threat?