Hi, Cindy! We are not frequent diners at the Hollywood Brown Derby because like you, I have kids that enjoy the character dining and quick service options. However, when we go, I like to remind the girls that this is Mommy's vacation too, and if they don't let me choose one meal, it may be the last time I remember how to drive to Walt Disney World. That's very effective in my house.
Once they are there, however, they always enjoy the meal. My nine year old now orders from the adult menu, and she finds more than enough options to appeal to her maturing palate. My five year old loves the tempura fish sticks, and I think if they added a character here, this would be the only place she'd eat - she enjoys the food that much!
You can do things to help keep them entertained. You can look around the restaurant at caricature drawings of various celebrities, and my girls like to look around the walls to see if they can find people they recognize. We've also had servers who have offered to bring the girls their meals a bit more quickly, which can sometimes help.
I think if you have something else for them to do while they wait in between courses - like a hand held video game, some trivia questions, or other game you could play at the table, it will help to pass the time and make the meal more enjoyable. But I say go - it's your vacation, too!