AreWeThereYet - from a non-smoker to a smoker, I thank you for your consideration. Any designated area on the ship should not be a problem for a smoker to light up. As for the balcony thing, I would again just use good judgment and common sense. If you are out there all by your lonesome, fire up. If you know there are others around you, then it is a judgment call...use your good judgment.
My only stake in this "discussion" (since I am not allergic) is that I end up with throat/bron ulcers and ear infection from prolong exposure. After one sailing on the Holiday, it lasted for several weeks. (We had a really smoky crowd in Karaoke - which is one of the main reasons I cruise.) But since Carnival implemented the designated smoking areas, I stick with larger ships and have not had a problem. I don't gamble, so avoiding the casino is no problem and the larger ships have karaoke in the smaller (but non-smoking) theather. So it has worked out well.
Sadly the other reason is just personal. I have buried one sister, one BIL and SIL and a grandmother because of cigs and what I witnessed them enduring before their death, I would not wish on my worst enemy (much less myself).
On the flip side, I love to smell a good pipe or cigar. My Dad smoked a pipe all his life and never had a problem with cancer.