Just my opinion and comments for what they are worth.
Don't count on any priority with dining reservations. Not even sure what a "Main specialty restaurant" is. Is it the MDR, or a specialty restaurant? The concierge service is meh. Sparkling wine, so so. You can get fresh fruit from room service or the buffet. We've always found the pears to be no where close to ripe, bananas over ripe. Just ask your cabin attendant for a different pillow. Unless it is an M class ship the cabins are no bigger. Whey do you need a cabin to sleep 4 if there are only 2 of you in the cabin?
There is no guarantee you would get both upgraded. What if your kids do and you don't?
Food for thought.