Yep, this is a tough one as the approach the investigator is following is important. Ultimately any story will need a trail of clues. I think the key to people having fun is for there to be multiple paths to the clues. A fixer would try to find clues by talking to people, Cops could call in the forensic lab folks (and interview people), Techies would have their own tools (scanners, sensors etc.) to give them help. So it almost seems there will have to be a technical based clue and a person based clue at each stage, so any Archetype can complete the quest.
Also want to second C-dogs' idea that a cool story will help a lot.
Also want to second C-dogs' idea that a cool story will help a lot.