My kids are about the same age as yours. I would tell you AKV is the better choice, hands down.
POOL - The pool at Kidani Village is awesome. It's almost worth spending a whole day there just relaxing.
THE COMMUNITY HALL - AKV has an awesome room set up with lots of activities for kids. OKW has the same sort of set up, but it simply pales in comparison. AKV has a huge tv with a Wii, a bank of tvs with PS2s, pool, and many other activities. We couldn't hardly pry my kids away from there to go to the parks they enjoyed it so much.
ON-SITE DINING - While neither one has very good on-site, quick service dining options, I would rather eat shoe leather than eat at OKW. At least you can walk from Kidani Village over to the Marra at AKL and get zebra domes.
THE ANIMALS vs. THE RELAXATION - OKW is great for a relaxing time, but AKV provides the same environment, just with bongos and zebras.
I think you will find either to be an excellent choice, but you phrased the question around your children. IMHO I think AKV is a much better choice.