We were at DQ on Thursday with our 2 year old son and much older one. The 2 year old loves the skee ball, pushing ANY buttons, and on the 4th floor where they use to have the pay area, there is now a small kid's area with pint size machines. He loved to play the catch the popcorn game. We did notice on our last 2 visits to DQ (thursday and about a month ago) that alot of the machines were broken. Just FYI, DQ has THE best cheeseburgers on Disney property.
As far as being worth it, it just depends. We have PAP's and can come and go as we please. I get tired of DQ after an hour. DH and DS(12) could spend all day there.