Hi Laurie,
Welcome to the Moms Panel! The swimming pool is a big factor in our resort choice, so I've spent a lot of time researching the various options.
I would suggest Coronado Springs Resort. What I really like about their feature pool is that is is wide open. It is easy to see the entire pool from almost any vantage point. Some of the other pools on property have coves, or corners that can obstruct your view of the entire pool. The Dig Site at Coronado Springs features a very large pool with waterslide. They also have a great playground right there as well.
Coronado Springs Resort also has some fantastic quiet pools, so there will be plenty of swimming options for your child.
To help you make your decision, I suggest you visit
www.allearsnet.com. If you click on accommodations, they will give you a full library of detailed photos of every Walt Disney World resort. They are categorized by level, so it's easy see all of the moderate resorts.
Good luck with your decision!