I've been to BB with my then 7 and 11 ds and 3dd. They had fun and they are not dare devils. There is a lazy river (sit in a tube and go around) there are large slides and small ones in the kiddie section. The kiddie section might be more their speed, but maybe they'd be too big now that I think about it. Probably all of the kids were 5 and under. There was a section that they loved. You held on to overhead ropes and walked across pieces of "ice" and they had zip cords that dropped you in a pool.
If your kids don't like the slides or rides, than I would say Sea World. We are going there ourselves for the first time in May. I personally hate water parks, my kids are very dissapointed we aren't going.