Yes it will be crowded, but less so than the other parks. Seaworld isnt like Disney when it comes to big crowds. Crowds at Seaworld get reduced when there are several shows going on. People are at shows instead of walking around. If you can plan your day ahead of time, you will have a more enjoyable visit. I say its worth going. Especially since the new Shamu show should be up and running by that time.
As far as if the shows are worth it. I think they are. The night shows are so much better than the day shows. Shamu Rocks, which is the nighttime shamu show, is so much better than the current day show. The Sealion night show is better than the day show. And the fireworks are pretty awesome.
Last year Seaworld had a half price ticket if you came into the park after 3:00pm for the night shows. This could be an option if you dont want to spend the whole day there. I dont know if they will do this deal again this year, but its worth keeping a look out for.
