I thought the plot of PST was excellent, and I know I'm not alone, it had absolutely nothing to do with BBEG taking over the world, it was a personal story of one man trying to understand himself and come to terms with the mistakes he has made. That was it. I know it's definitely an outlier in that department, but it shows it can be done, and done well. I do agree that you can have a heroic epic fantasy experience without Tolkienesque themes, perhaps some will disagree saying it must take or share some forms of the Hero's Journey, but I disagree, and we've been shown examples of cases that do not follow that pattern, albeit with a small sample size.
No idea what PST is, sorry. I don't doubt that a different plot could be done, it's more that I'm surprised that nobody has done it. I don't know if anyone here remembers a NWN1 called "Citadel"? IMO the best mod for any game I have ever played. DLC-sized with excellent writing, all original enemies, interesting companion and other characters, all set in a unique environment. It even featured some interesting philosophical concepts. Speaking of which . . .
Campbell's "Hero's Journey"/Monomyth stuff is nonsense as it has nothing to do with Jungian psycho-babble.
