I understand now. Just because this isn't what I would do doesn't mean it's not right for you.
I've never been to any of the water parks, but I've heard from other posters that 1/2 day at a water park is plenty, although maybe that's not your idea of a good time.
All that being said, if I had 7 days of theme park/water park split, I'd be doing 6 days theme park and 1 day water park. But I could spend an entire week-long vacation and go to DAK every day! And with SWGE, DHS has turned into an all-day park.
After you have 4-day park tickets, the additional days are not all that expensive. Just something for you to think about. Planning is half the fun! And when you're not planning or there, reading the DISboards is almost as much fun!