You can't take up hold space for other uses and not allow for baggage. The amount of baggage is unbelievable. A full 747 will have almost full holds. Where will the extra bags go? As for raising floor levels, the cost is astronomical.
How would you like to be down in a baggage hold container in an emergency evacuation? Sticking seats down there with low ceiling levels, and you have not considered the curved fuselage taking out half the floor area? And no exits- still to be installed. Whatever your idea- it's a non starter I'm afraid!