To me this is simply a different take on difficulty levels. I've always been surprised that more games don't have selectable difficulty level, or some mechanism to allow the game to 'scale' to the player's ability.
This approach seems to about taking a more flexible, on the moment approach to difficulty vs switching it about yourself as the player. But I don't see it ruining anything particularly as in the end its simple a different approach to achieve the same thing.
Take, for example, Silent Hill 3, you had two difficulty settings on that. One for combat, the other for puzzles. So you'd encounter essentially the same puzzle on playing, but if you had puzzles on easy then the clues made it pretty easy to solve, if you had puzzles on hard you needed to sweat your brain to work it out. Different players could feel the same sense of 'I got it' but each would be given a different level of challenge.
For those games/developers who want to seperate the better players, or let them know they are better, that's where stuff like Tophies, etc. come in - or any kind of scoring. So again, taking Silent Hill 3, if you want to 'score' the best you have to tackle the game on hard.
In the end it's about trying to satisfy different players, some who want to know they're in the top ranks, others who just want fun and to always be able to get through the game.
This either requires games to rigidly focus on one group - or the ability to alter the difficulty.
Increasingly, particularly titles like Mario, etc. I would expect developers to move towards the latter.
Try to be reasonable... its easier than you think...
