Context, how does it work. They fought for a minute or two to set up Obi-Wan's sacrifice. It was never focused on the saber battle. The entire scene is about Obi-Wan passing the torch to Luke and showing him the power of the light side.Riiight, and the scene in Mordor in LOTR Return of the King is just a hobbit and a caveman fighting until one falls into the lava and dies but nevermind if that was shown 90% through dialogue instead of action. Let's just reduce all cinematic storytelling to stage-plays.
Like I said. There is nothing particularly "bad" about the saber battle and it was never the focus or important takeaway from Vader meeting Obi for the last time.
So again if your summary of the scene was that it is "so bad" because of their very brief duel, I'd say you're putting far too much stock in how important the actual fighting really is.