Rapunzel- When are you going? Diagon Alley is opening some time this summer so there will be huge crowds, and it will take longer to tour.
And although you could do both parks in a couple of days, you won't have to. You will have time to explore all the little details, pool hop to all three resosrts, eat at all three resorts it you want to- just take your time and relax.
We have gone for a week and not been bored. We like pool time, my DH and DS like the gyms, I like to walk thru the resorts and absorb it all. You can do mini golf and BMG. Even take in a movie if something good is out when you are there.
Each resort has shopping and places to snack. All the pools are quite different. There are luaus and Velvet Sessions.
A lot to do and no need to rush.
I hope to be planning a trip soon!