I've read lots about the Big Thunder Ranch BBQ. Would you recommend this over Medieval Times or Pirates dinner?
A visit to Medieval Times or Pirates is going to take you away from the park for 2-3 hours. You'll have a great time at either but it won't be Disney and the food is marginal but OK.
Big Thunder takes far less time, but the entertainment could be considered a little dull and boring for the ages you mentioned. They do try to draw in the audience and get them to participate in sing-along and things like that, but there are a LOT of tables and it is not theater seating.
The suggestions from others are largely dining venues only whose primary source of "entertainment" is the theme of the restaurant.
Both Pirates and Medieval times are highly engaging entertainment experiences, that include a meal.
I hope you can envision what I'm trying to communicate here. It really does depend more on what you are expecting. How much time are you willing to spend away from DLR? How much are you willing to spend on a meal? What type of things entertain your kids, keep them engaged?
Someone else suggested a character meal. Our kids really enjoyed Goofy's Kitchen. It is mostly about the meal, but there are characters and they even encourage the kids to get up and dance with Goofy. It is more than just sitting at the table while the characters wander by. It is buffet style so it can be a pain for parents of younger kids who have to help their kids fill their plates.
I hope you are getting the picture of what I mean here.