“Time spent” is not a measure of challenge. It is not a measure of content.
“Risk” is not a measure of challenge. It is not a measure of skill.
Too many games are built around time, not content or challenge.
Too many gamers want to be coddled instead of challenged.
A few relevant links, thanks to some very eloquent bloggers:
The Lost Quadrant by Stubborn
The “Twit” Generation by Chris
Redefinitions by Tim
edited to add: What is Skill? by Gazimoff
…and an attendant point: I submit that it’s the desire to string along players and get their sub money that is the root of a lot of the changes in game design that veterans are fussing about. If these MMO things were sold via “single sale” pricing, the design could easily be “take it or leave it” and pretty much left to be accepted on its own terms.
edited again to add: Class Warfare by Azuriel
…and then there’s an old relevant article of mine, just in case you need some filler, Full Spectrum Challenge