I think it's going to be a bit difficult to get a fair comparison at this point seeing as though AoA just recently opened its first building at the end of May. Like the other posters here I've stayed at WL on multiple occasions and loved the resort. They have a mini-waterslide that your 5 year old and your 11 yo would love, although you'd have to make a judgement on the 5 yo. My son was 5 when he first went down it, but he was a decent swimmer at the time. Just make sure someone is down towards the bottom of the slide when they come down for the first couple of times to be sure.
That being said your kids may enjoy the surroundings of the AoA resort a bit more. I've heard that they have activities that teach you how to draw animations over there and from what I've seen online the theme is pretty cool. The price on the other hand can be steep in some of the AoA rooms, so be careful.
You will be able to take a nice boat ride from WL to MK whereas at AoA you are somewhat isolated away from the parks. I would suggest that you sit down with your kids around the computer and take some of the online guided tours of both resorts and see if anything sparks in their eye. Then make a decision based off that. Just be aware as I said that the Family Suite rooms at AoA can run you anywhere from 250-400+ a night depending on the time of year.