Normally, I like Leonard Maltin and can sympathise with his reviews but he seems to have watched a different film here entirely. It is not really a revenge story, "by-the-numbers" or otherwise. There is a man with a mission here but cheap vengeance isn't his goal. The leads do an excellent job of portraying antagonistic personalities coming slowly to the boil in the claustrophobic world of the fencing salon as the characters evolve. And they do evolve.
As for Errol Flynn doing it better, that is a fatuous comment in the extreme. Apart from his swordfight on the beach with Basil Rathbone in "Captain Blood", his fencing always looked very stagy to me. The last fight in "By the Sword", by contrast, is the single most vicious fencing combat I've ever seen. It is the only time I have ever had the impression that the combatants actually intend to kill one another. A brilliantly choreographed sequence.
As for Errol Flynn doing it better, that is a fatuous comment in the extreme. Apart from his swordfight on the beach with Basil Rathbone in "Captain Blood", his fencing always looked very stagy to me. The last fight in "By the Sword", by contrast, is the single most vicious fencing combat I've ever seen. It is the only time I have ever had the impression that the combatants actually intend to kill one another. A brilliantly choreographed sequence.