We've been to WDW several times in the past 3 years. When we ask our 7 and 9 year old what was their favorite part they always skip the parks and talk about the fun resort days at BC.
Stormalong Bay is their favorite pool and definitely the main draw to the resort. There are usually some kid friendly activities around the pool.
What is not really discussed is the lake. The man made beach has campfires, movies under the stars, and day time lounging. You can also rent small boats, and go fishing from the dock. Of course no swimming in the lake, but that's what the pool is for.
The best part bout BC is the proximity to the Boardwalk. Its a short walk or small fairy ride. Each night street performers come out and provide FREE entertainment. Magicians, jugglers, musicians - it's really cool for kids and grown-ups. The restaurants here are the best value on property. We stop off at the brewery during each visit. Great shops too.
Boardwalk has 2 and 4seat bike carts for rent. You can take off in one of these and get some exercise going around the lake. The serenity of the lake and the bright lights of the Boardwalk are best appreciated from the seat of one of these contraptions.
If you are still looking for things to do, there is an arcade (yawn) and a nearby miniature golf course (costs money, we've never been there.) Swan and Dolphin have several fancy restaurants within walking distance, but they are not Disney operated.
So in short, I would say there is plenty to do at the Beach Club Resort!
Have a great time when you go!