For us the smoking thing is something we just have to put up with, it's better now it is banned inside, it was impossible to enter the Pub type bars before.
I think itinery is the first thing for us, as we haven't been everywhere yet. We haven't been on a ship that we wouldn't go on again, we have preferred some over others. Price is important to us so it's always a compromise between what we want & what we want to pay. We went on the Azura for a month, it was great value especially for Xmas & new year, but there is a limit on what a holiday can be worth, it's only a holiday after all. I find it very difficult to believe that some people go on several world cruises (or so they say) decent cabin + spending must be £40k for two. I think a lot of people go on imaginary cruises, especially on sites like P&O, Cruisedot etc.