I would advise to skip the dinner package.
We have tried the dinner package twice in the past and between rushing to get to the restaraunt, waiting to be seated, and then having to show up at the entrance 1/2 hour earlier just to sit on the side of the theater is ridiculous.
The second time we tried the package, it rained, and they cancelled the show. I can't remember if they promised reserved seating another night, but we left Disney the next day.
We were at MGM 1/2/04 and the park was packed. We went 1 hour earlier than showtime, and they had just started seating the crowd. We got seats right in the center about 15 rows back. The early arrival was so much more worth it.
The most annoying thing about the dinner package is the terrible seats that are reserved for you. You are in the last section on the side of the amphitheater. You can certainly see the show, but the middle is so much better.