Let's just ask this: Does your 4 year old LOVE animals? As in, is she OBSESSED with African wildlife? If the answer is yes, then stay with your AKL reservation. If not, move to WL. Both resorts are about equal in terms of amenities. AKL may have an edge where the pool is concerned. However, I'd say WL has an edge as far as having more to do recreationally speaking. There is Ft. Wilderness right there, you can rent boats (would be a fun thing for you or your DH to do with your 4y/o one day while the baby naps), take boats to the Contemporary and then you have monorail access to those three MK resorts for dining, which is a huge plus. I could go on. WL is fabulous, and also has plenty of wildlife to see on the grounds (ducks, birds, rabbits, otters, deer, etc). At AKL, you might feel a little isolated at the end of the day.
On the other hand, if your DD absolutely would FLIP upon seeing giraffes and zebras outside her window, then you would be a fool to NOT stay at AKL with a savannah view. It really depends on what your family needs/wants out of a resort.