1 park per day... is that the 4 WDW parks + 2 water parks or 4 WDW parks + Universal?
If it's the first version with the water parks, I'd only ask if you wanted a Disney Springs day. And, well, you are paying a premium for having a pool at your hotel (which one, btw) and might want a day to enjoy it.
If it's the second, with Universal squeezed in there, then definitely give yourself a day in the middle, if you can afford it. You'll be exhausted from your vacation, if you don't.
Fly in Monday: Spend the day coming down from the airport (or dealing with delays)
Tuesday: Magic Kingdom, as a single rider and having been 11 times I'm not afraid of lines.
Wednesday: Hollywood studios, Possibly split with a waterpark since HS is a half-day park RN.
Thursday: Animal Kingdom I've never been. my family usually does Busch Gardens instead.
Friday: Epcot The big spending day.
Saturday: Fly home, Cry, wait for the items I sent home using the Disney Package Delivery Service instead of packing them in my suitcase.
OR
Fly in Sunday, Come down from the airport / deal with plane delays
Monday: Magic Kingdom. Single Rider, not afraid of lines.
Tuesday: Hollywood Studios, Waterpark. Same reason as above.
Wednesday: Rest feet at hotel, maybe resort / monorail hop if I feel the yen.
Thursday: Animal Kingdom, give it the ol college try.
Friday: Epcot, Spend that money.
Saturday: Go home, Cry, Wait for package deliveries.