What Huensao pointed out is really interesting. Is the inability to gauge how deadly an encounter is Good or Bad? It also is echoed in KODT, when Heidi Jackson wanted to get rid of all the deadly risks and installed a "time out" system. It also follows question is the sense of risk essential for something to be heroic or worthwhile?
Challenge Ratings, HD progression, Encounter Levels, etc. All figure into making risks and death predictable. So when the system becomes this transparent, that all odds of success can be calculated with encounter formulas etc. what happens to the immersion?
uncertainty and risk cannot be divorced, both in a situation and in the meaning of the words. Once certainty kicks in, you throw away risk and everything just becomes a repetitive ritual... Its just a matter of going through the motions.
Some of the Old School Rhetoric is about risks. Its easy to take on great risk if characters required little personal investment and the process of attachment came with the achievements garnered despite odds. Until there is a way to make believable and lovable characters easy to generate, i think overprotecting the investment will always be a problem in achieving real adversity.
I guess, character detailing being achieved on a installment basis. Where the player has access to a huge Roster of Characters and through the campaign gets whittled down to survivors. These survivors only get their character made fleshing out per session they survive.