Let's say the casual person averages roughly an hour of time playing an mmo a day. The hardcore averages... well lets just say a lot more than that. So in the end, what do you think is the proper difference in power level between the two? You can just throw out a percentage if you like: "the hardcore should be x percent more powerful than the casual". Or you can get as detailed as you like. And to spice things up: should certain areas of the game put players on a completely equal power level no matter how much time they invest?