Spoilers, if you care.... For the end of season five.
Duncan is crazy again, and killed Richie. Did we just do this? Didn't he just go nuts and kill his friends? Couldn't they think of something new?
Worse, worse... last episode of season five and Duncan is thinking he might be crazy, and Methos and Joe think he's crazy, and Richie calls and says he saw Joe when Joe is standing right next to Duncan and it seems the most important thing would be that Richie was seeing things too... so why doesn't Duncan say so? Methos and Joe are standing right there. And Duncan runs off without saying anything. And kills Richie.
This is about as dumb as, "Let's split up."
"I think I'm going crazy, but rather than stay with people I trust, I'm going to run around alone and do who-knows-what."
And I was thinking that those writing Highlander were actually rather good.