Lots of different angles brought up, but I'm going to tackle the forgone conclusion aspect. Reading Star Wars, you always know the good guys are going to win, right? Well the Darth Bane trilogy threw that one for a loop because it stars the bad guys. The question there wasn't so much if the bad guys were going to win, but how the heck was this series going to turn out? By the third book, the question was who was Bane's apprentice going to be? I thought that series did a very good job of keeping the reader guessing on what was going to happen.
Another good example of a book where forgone conclusions need not apply is Riptide. If you don't mind getting the book spoiled for you...
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You would normally think, 'hey, this is Star Wars, good guys are safe.' Well Kemp throws the reader for some serious loops. He rapidly kills off the people the reader perceived as the bad guys, he killed off the main good guy, he confused the reader with a multitude of clones and mysterious plot threads that leaves you guess whose a clone and whose not a clone...it was sheer, enjoyable madness. You had no idea what to expect.
If you look at the NJO, several big main characters were killed off. It was unexpected and it really changed how people saw Star Wars. Suddenly the good guys weren't safe. The only forgone conclusion was that the Vong would defeated, and even that was questionable. If they kill off the good guys, what's to keep them from having the bad guys win?
So generally, yes, we know the good guys as a whole will triumph over the bad guys as a whole in each story. But the authors and comic writers generally do a good job of packing in a lot of small surprises for the reader.