Good point Susan. Filling the Oasis is the equal of filling two ships and it ought to be looked at that way instead of it being one "larger" ship.
5400 passengers is double occupancy. With all berths filled it is well over 6000 passengers....and don't forget the 2100 crew members.
I am excited about cruising on the Oasis. I am also more than a little curious about the mass of humanity and how it will be managed.