@flyingsolo: but it also depends on how much certain pokemon are seen. Bronzong is way more rare now than it used to be. Scizor, otoh, is everywhere.
On Salamence, Flamethrower still easily 2HKOs Skarmory, and Fire Blast just OHKOs it, provided you hit. On something like Flygon (and by extension, Garchomp), you need Fire Blast for the 2HKO, I believe, especially if you don't want to invest anything besides a neutral nature.
thats not how you look at it
you dont say
"hmm ill go with flamethrower, but if i ever match up against a bronzong ill probably lose. thankfully, bronzongs arnt that common! I'll only lose 8 percent of the time! or whatever the percentage is for bronzong"
as for 2hkoing skarmory, wouldnt you rather ohko it so it doesnt whirlwind out ur dragon dance
rather than: "ill dent that skarmory pretty hard with flamethrower, itll roar me out and sure my salamence will take another 25% when i bring it back in at which point its useless to me, but at least I taught that skarmory a thing or 2!"