I think the answer really depends on what you like to do. DH and I love coasters and simulator rides. We also prefer the convenience of being able to walk to both parks and to City Walk...no waiting for buses!!
Four days in the parks will give you the opportunity to take your time and and do your favorites over and over again. If you plan pool time into your vacation, you are in for a treat. The pool areas at all three hotels are fun and relaxing...but all very very different. Unlike Disney, pool hopping is ok. We stayed at Royal Pacific but spent our pool time at Hard Rock.
We stayed 6 days and it was wonderful..never a boring moment.

Lots of time to relax. We spent one afternoon just strolling through both parks soaking up the atmosphere. I'm sure you will have a wonderful time.