Slam Dunk - no question: BCV pool is superior.
I agree with the previous poster who warned you of the size of the pool complex. Will be difficult keeping your eyes on all 4!
I would also warn you to be very careful with the kids in the floating pool! The pool is very deep and the current is strong. Would not recommend any of your kids go in that alone.
Regardless, all pools are staffed with a large number of life guards who do a good job controlling the pool.
With kids that age I would recommend a pool hopping day! We used to head out with our kids and try and hit 7 or 8 pools in a day. The rule "No more then 45 minutes at any pool". The kids loved it. We always do this when Grandma was with us so she can shop and see the different hotels.
I asked my kids to rate all the BCV pools. They are:
DVC Pools:
1) BCV - The slide is awesome. Lots of diversity.
2) SSR - Very nice slide - usually not too busy. Zero entry good for the little ones.
3) BWV - Very cool slide, pool can get busy.
4) OKW - Great setting - new slide is not that great.
5) VWL - Nice setting - pool and slide are not that great.
Other resorts:
1) Poly - Great slide. Zero entry is good. If you listen you can hear music under the water!
2) GF - Nice slide great setting.
3) AKL - Slide is boring - but the zero entry is nice. Gets busy (and no pool hopping - just guests).
4) Coronado - Slide is not that great - but it looks impressive!
5) Car. Beach - Lots of diversions for the kids.
6) Port Orleans - Again, lots of diversions the young ones will like.
7) Contemporary - Slide is not much, but, great views over the lake.