Well you are aware you have to book the specialist resuarant when you are on the ship and pay the extra, personally we are both difficult when it comes to food but we found most night 2 items on the main course menu we could have gone for and had no complaints about the quality/taste/service. On the table problem you should have spoken to the Maitre'd and he would have tried to resolve the problem as it would not be great for the staff covering your area as the usually on get 16/18 covers I think and 10 were missing from your table alone.
There's nothing stopping you booking the speciality every night if you so wish, but is there really enough choice of menu for 12 nights?........Wilba.
As others have said, provided you're willing to pay the (how much is it now? 25? 30 dollars per person?) extra charge and can book your table for each night, there's no reason why you couldn't.
We sailed on Millennium in 2004 and ate twice in a week in their 'Olympic' restaurant, finding it wonderful. However, on Summit last April, a visit to their 'Normandie' restaurant was less successful - a main course dish of mushroom risotto was horrid.
If you find yourselves on a table with no fellow guests, try asking the maitre d to move you to one with companions - he will usually do whatever he can to accommodate your wishes.
We have cruised with Celebrity many times. We have eaten in their main restaurant only once!!! Always eat in the Speciality Restaurant. As regard to choice the staff are great and offer specials outside the menu. Great food in all the speciality restaurants we have eaten in.