I do believe there's some variances between cruise lines on what they are targeting.
For example, unlike Celebrity, Royal Caribbean, Carnival and NCL have taken paths to regenerate the entertainment offered onboard. They've upgraded from standard production shows, and basic "headliners" of comedian, juggler, ventriloquist templates.
As far as dining, I think the cruise lines all got a bit of wake up call, when NCL debuted Free Style cruising, with all its options and choices, and got a pretty well deserved response, and buzz.
Since then they've all attempted (in sort of their own way) to upgrade on those ideas.
Of course, much of the innovation in that area comes from what is "happening" on land in the restaurant business, not from their own imagination.
The hottest restaurant "thing" on land is the young, up and coming, celebrity chefs. Even in a down economy, the hot thing is hot chefs, chef's tables, tastings menus. and the cruise lines are attempting to take bites of the same apple.
On a somewhat upscale cruise line like Celebrity, I'm not surprised they'd direct their attention to that, as opposed to entertainment. They are probably guessing their passengers are the same ones paying extra for the more "in" restaurants at home.
If many more people are purchasing the various beverage packages, dining in the extra charge restaurants, and booking some of the more expensive Spa cabins, etc. I'd think those people might start looking at and comparing Celebrity to the more upscale luxury all inclusive lines (including drinks, tips, even excursions), which after adding in all expenditures would probably compare quite favorably when the final bill is tabulated.
The luxury ships certainly focus less on theater entertainment, and more on enrichment programs, excellent well known guest lecturers, etc.
Celebrity seems to be aiming for the luxury light market. Those who enjoy it, might find they can get the full luxury model with a very similar sticker price.