Dumb uses of fire in D&D
Number One: using oil flasks as molotov cocktails is idiotic. Glass bottles were super-expensive. Oil would be kept in leather pouches or possibly clay pots, and no one's carrying clay pots into battle.
Also the oil you had would be tallow, lard, or olive oil. Not gasoline. Whale oil in Scandinavia. Possibly hemp in Asia. An olive oil fire isn't a rating conflagration.
If you need to fry a bad guy, cast your damn fireball
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