It is interesting that Celebrity has the same "designated smoking rooms" situation that all lines (of which I know) had ten years ago. It worked well then, and I don't know why the lines keep trying to fix something that "ain't broke."
I agree with the post above in the suspicion that insurance carriers are behind this whole thing. If you dig deeply enoungh into any "problem" or controversy, you often will find that insurance carriers are at the bottom of it.
There are a couple of additional aspects that have not been discussed on this general topic.
The first is that since Regent has just "tossed out" about 25% of its client base (the approximate percent of Americans who smoke -- probably higher for Europeans and Asians), Might it be that resulting vacancies on their cruises will bring on more "sepcials", "discounts", and the like?
The second is the question of will this policy change "stick"? It's like the situation where an airline raises it fares on some routes. If its competitors do the same, the increase "sticks". If not the first airline always rolls back the fare increase -- because the laws of supply and demand say it has to do so. I think Regent's competitors are Silversea and Seabourn (though some might disagree with this analysis). If Silversea and Seabourn do not follow Regent into "smoking restriction land", it is my fearless prediction that the restrictions will be short-lived.