Arcueid
The content is generated upon the player's preferences. E.g. statistical analysis of the gameplay.
I've been arguing for this in various MMOs for 13 years... mostly to deaf ears unfortunately.
Arcueid
E.g. knowledge vs grind. Everything is available and the outcome just depends on your amount of knowledge and not on the 0.04% drop chance for something good.
Unfortunately someone will invariably "post the secrets" of knowledge in a public venue shortly after they are discovered by the first few hardworking souls. In the past (c.f., Hidden character key to support unique character content) I have suggested that the finer details of "knowledge" could be randomized based on a random-seed for each character. The response was that assigning a random-seed to each character would be unfair; some would get better seeds than others. How this is different than randomized drops (or real life luck for that matter), I never understood.