I've seen the show a couple of times, and agree that there is no real cohesive story. However, the musical numbers are done really well. At the Q&A session after the show someone asked about the lack of Stitch in the show, and I am sure that the creators realize that that will be an "issue" for people watching. I really enjoyed all the numbers, thought Jungle Book and the three princesses were the best, and though Under the Sea has been done too much at the parks, I really liked the dancers, especialy the two bubble guys.
As for seating, the seating area is small enough to see the show well from any area, however, the center gives you the best effects. Also, there are bubbles and streamers that come from the ceiling, and the streamers do not hit the back half of the audience. If you have children who will have a better experience catching streamers as they come down you might try for the front half rather than the back of the audience.