I'd just keep it simple and ask people to respect each persons needs to the best of their ability when sharing space on a ship of 3,000 + souls.
In terms of your suggestion of dedicated balcony cabins at the stern (if I had that right). we should not go in that direction as you take away my right to choose a view I might enjoy on a ship as much as you do.
The "smoking cabins" wouldn't necessarily have to be on the stern, facing aft. They could be along the sides aft.
I do have to chuckle a bit when it's said that would limit the choice of the views. The choice would stll be available, but people would know in advance they are booking in area where smoking is allowed, and might occur. Plus they wold be assure there would be no smoking allowed in cabins or on balconies on the other 80 % of the ship.
After all, for a comprise to work, there has to be a compromise
Of course they could just set a policy or no smoking anywhere, and let smokers decide if they choose to cruise on the ship or not. As a smoker I'd be ok with that too. It would eliminate the doubt and I'd make the decision.