I think your kids will have a great time at the park. As for DH, some people will just never "get" animal parks, maybe he's one of those, maybe the growth in the park will make a difference, maybe he'll be able to enjoy it through the eyes of the children.
I'm sure your kids will love the shows (they are a perfect age for the Pet's Ahoy show, which is perhaps a touch too cutesy for older kids), they will have a great time in the kids play area ( Shamu's happy harbour) and I'm certain they will love feeding fish to the dolphins,sealions and rays. At there age it's worth searching out the "Tide Pool" exibit, which is easily missed. Younger kids have a great time getting their hands, arms and occassionally by accident their heads

LOL, into the water.
I believe your DS will be about the right age to have a chance of being asked to star in the Whale and dolphin show. If you'd like him to be considered it's worth getting to the Whale and Dolphin stadium 30-35 minutes ahead of the show ( use the spare time for a drinks break). If you see a CM wandering around with a clip board ( this has the disclaimer/waiver form you'll have to sign)get your DS to go up and ask him some questions about the dolphins (what are their names, what do they eat/feel like etc) . The CMs have to find a kid for each show, if they can find a kid thats the right age, interested in the dolphins and confident enough to ask the questions it's usually a done deal. The CM's aren't too keen on this task because if they leave it too late they either are struggling to find a kid (which spoils the show a little) or end up having to beat off a mass of begging appealing and pleading faces (upsetting the dozens that don't get picked).
While I agree with Catlady that previously trying to eat at SW between 12.00 and 3.00 or 5.30 to 8.00 could be a bit of a task the new restaurant areas should ease that congestion at the restaurants considerably.
I hope you have an enjoyable day.