I'm not really sure what the "like FR or Dragonlance" means though. Can it also be "like Oriental Adventures," for example, or is that too far afield? It's still a fantasy medieval setting, but it's a far cry from FR or Dragonlance.
But then again, so is Dark Sun. How closely is it assumed that we follow the PHB? Does eliminating some classes and replacing them with others ala OA count against us, or is that fine?
I know I'm probably getting more specific than you want to answer, but I'm really vague on what that whole thing means still.