Lanefan
Victoria Rules
Disagree, and then agree; and it all depends on what side of the screen you're on.I don't think there is any need to have a general theory, and party construction shouldn't have anything to do with how the DM presents challenges. It changes how the party approaches those challenges.
From the player side, having or developing a general theory makes sense - even in-character - once a party has gone through a few adventures and become familiar with what's out there. I'm fine with this.
From the DM side, though, you're absolutely right: the challenges should be presented neutrally without regard for what composition of PCs the players happened to bring along this time.