I have seen Fantasmic a few times and I like it. I agree the croud it attracts is just insane, but it has 1 redeaming feature.
IT CLEARS THE REST OF THE PARK OUT!!! During the shows, its the best time to hop on crouded rides since it will take the lines down by 50%! Then after the show a good portion of the people leave. Even less lines!
All of us have most likley seen it more times then we can count, so missing it is not a big deal. But a 10 min line on the Matterhorn is! Just dont be near Mainstreet or Fronteerland when the show ends.