carrousel:why would you want to change back? am I missing something?
A restaurant has a couple limiting factors associated with it. One is seating capacity -- you can only seat 125, for example. Another is kitchen throughput -- you can only cook 'x' number of individual meals at a time. If either of those are stretched, then people are going to wait, either in the lobby or the bar while waiting for a table, or at their table waiting for the salad/entree/dessert.
The way you make a restaurant with a fixed kitchen throughput able to serve more people at once is by having those people all have each dinner course at the same time. All of them have the soup at the same time, all of them have the salad at the same time, all of them have the entree at the same time. This way the kitchen is not simultanteously mixing a [large] batch of caesar salad and dishing it up while preparing and dishing up 6 entrees, while also ladling out 12 soups, and also carving up 4 key lime pies.
It's far more efficient: a kitchen can feed more people by doing one thing at a time in large quantity than by doing eighteen different things at the same time in smaller quantity. If you don't believe me, try it at home this Txgvg. Invite your whole family but don't give them a dinner time, and feed them whenever they show up.
This, of course, limits the diners' choices. There are two dinner starting times on the ship, and you have to hit one of them. You can't split the difference and start at the entree point of the early seating and progress through the salad course of the second seating. It don't work that way.
Diners who don't like their choices limited like this complained, and apparently Carnival though they could try to accomodate it, so they're trying it.
But the problem with individual dining is that [big surprise!!] most people like eating at a common time -- generally between 6:30 and 7:30. If a dining room holds 1000 at a time, and there are 2000 who need to eat, and it takes them 1:15 to 1:45 to make it through 5 courses, you obviously can't have all 2000 trying to get seated and eating starting between 6:30 and 7:30. The line will be out the door in no time at all, and people will be very very miffed very very quickly. Hence reservations, and some people being forced to alter their plans anyway to start eating at 9:00 or at 5:15.
If most people continue to go with an assigned dining time, then it will be possible for some to do the individual dining; if most people want individual dining, then the restaurant will be choked at times, reservations will be needed a lot of the time, people will become dissatisfied, and -- depending on HOW dissatisfied they are -- assigned dining times may be reimplemented. It's a matter of how selfish most people are going to be about it.