Definitely...especially if you have kids.
When we went they were running a special where you pay for one day and you can go back one more day within 7 days for free, so we took advantage of it.
I love Sea World and there really is a lot to do. Definitely MAKE SURE YOU SHOW UP EARLY for Cirq de Mer & Clyde and Seymour Take Pirate Island.....they have some pre-show entertainment that is hilarious.
Because the park was so empty we really did almost everything in one day, except (if you can believe this) Shamu! So we did go back a second day and did a lot of things a second time. It was too cold to do the Atlantis ride the first day, so I was glad it was warm enough on the second visit. And I could feed those dolphins and sea lions FOREVER!!!
They have a new restaurant where you can dine beside the shark tank. We didn't but it looked good (although a little pricey).
They are also doing some construction...it looks like they are adding some sort of dolphin experience to the park which makes me wonder what's happening with Discovery Cove.
But I told DBF I don't want to go next year because we ended up spending very little time in EPCOT, simply because we ran out of time.
You would have thought 10 days would be long enough.