The Bonhomme Richard was, as you say, far from being a first-class warship. That's why I say that John Paul Jones must have had a lot of nerve to take on the Serapis the way he did. But having a lot of nerve seems to have been common with fighting captains in that day (at least the ones we hear about the most). They had a strong honor system to live up to, and it seems to have compelled them to charge heedlessly into the breach even against quite superior odds.

This has provided much inspiration for fiction about the days of fighting sail, and the adventures of such characters as Hornblower and Jack Aubrey.