Hi Shari. It's good to see you again.
Having returned from a HAL cruise about a month ago, I assure you that you'll have a seat in the main dining room. Dave is correct that, at a minimum, you will be given the "As You Wish" dining option. It is also likely that you will get the time for which you are waitlisted. I was told that the waitlist is sometimes used to determine how many tables they need to set aside for traditional dining in the AYW area.