Here are a couple of ideas I have had for Sea World for a family area and a kids area. I thought of both before we knew that the kids area was being redeveloped and before we knew where Creatures of the Deep was going to be located. This is all blue sky stuff that I really don't think will happen, but I thought I would share none the less.
Someone earlier in the thread suggested a Paradise Pier-esque area. I've thought a general seaside boardwalk section would work well for a while now. It would fit on the reclaimed land that Creatures of the Deep is going to utilise and have a few family rides on the water's edge that you could see across the lake when you enter the park. I was initially thinking a relocated Carousel, plus a set of Flying Scooters and a Wave Swinger would be good choices. When cycling, the latter two rides would splay out over the edge of the boardwalk. The rest of the waterfront side of the boardwalk would have some seated areas. On the other side of the boardwalk along the park's boundary you would have a line of buildings, namely a fish and chips shop, a merchandise shop, and a couple of relocated carnival games (obviously have a bit more effort put into them than the current set of games).
The second area that I was thinking of was a SpongeBob-themed Bikini Bottom area. This is an idea I had when Sea World first acquired the Nick licenses so I thought it would be a good re-theme of the kids area. Some of the existing rides would remain and be rethemed to things like the boating school (convoy, with new "boat" vehicles) and jellyfishing (aero top jet, with new jellyfish vehicles). Not sure what would be the best thing to do with the frog hopper or Heege tower but I'm sure you could find something to theme them to with the help of Google. A Davy Jones' themed Zamperla Rockin' Tug installation wouldn't go astray either. To wrap up the area I'd say a Krusty Krab restaurant and a replica of Spongebob's pineapple house would be musts.
Anyway, bringing this back on topic a bit, the only thing I think that has a slim chance of coming true from that described above is that one of the new kids rides is a Rockin' Tug. I also think the suggestions that the new coaster would be a 80STD by Zamperla are on track too. Regardless, it's good to see Sea World putting in a bit of money to renovate this area which has really only had minimal changes since opening in 1999.