I'm new to these forums (and Avernum, having only played 6 thanks to recommendations from friends over on the Basilisk Games forums), but I'm not exactly new to narrative structure. *I's recommendations are interesting, but would probably require a lot more programming to work in interactive storytelling. Chekov was discussing foreshadowing in a linear narrative, and a big part of the joy of a game like Avernum is that it's not strictly linear.
The only way I could see it working, really, is if the programmer had other parties out there doing some of these jobs, and if you took too long, they might complete them first, or might end up dead because you had left some villain alive too long, or perhaps you could even end up meeting them and doing part of the quest together. The programming required for all of that would add a lot of development time, though. Not to mention dealing with the various possible player actions, including what if you decide to off the other would-be heroes so they don't steal your glory?
Also, some of these things could be answered simply by a bit of narrative showing that these opponents legends eclipsed their realities.
Overall, though, I've quite enjoyed playing Avernum 6. It has a good balance of challenging gameplay and interesting narration, with options of side quests to take on or not.
--Kreador Freeaxe
Kill 'em all, let the sysadmin sort 'em out.