Re: Why did Trip have to die in the final episode?
I don't think this is true. From what I remember Demons/Terra Prime was supposed to be 3 parts and the season finale, but when the news came in that the show was cancelled during the filming of IAMD plans were changed and B&B came up with TATV.
The Beebs were quoted as saying that TaTV was actually written during season 3 and would have served as the series ender if season 3 had been the last one.
Duckman: I'll never forget the last thing my father said to me...
Cornfed: "Careful son, I don't think the safety's on"?
Duckman: BEFORE THAT!!!