PlanMan, don't panic about going over the Christmas/NY holidays. We went this past Dec. 28-Jan. 4, and will return for the same dates this coming Christmas.
The crowds are definitely large, but I believe that they can be managed. Sounds like you plan to do the right things to make it manageable. We made full use of early entry mornings, fast passes, and the extended nighttime hours. We always took the afternoon off to go back to the resort for swimming, napping, down time, whatever. That helped us to be fortified for the evening back in the parks. We also saved time by carrying lots of snacks to graze on while in the parks so that we could do without meals in the parks until we were in our room. (Stayed in BWV studio, so had use of the kitchenette) We did our eating out on non-park days.
We also decided to make Dec. 31 and Jan. 1 our non-park days. We didn't feel like being shoulder to shoulder on NYE. Instead we enjoyed the Boardwalk area, the pool, DD, and we did a little resort hopping to see the Christmas decorations too.
So that's how we managed our time. We saw and did everything we wanted to, and even went on some of the super headliner attractions/rides 2 or 3 or 4 times. I've also been to WDW numerous times during Easter week over the years. Holiday times are workable if you're ready to manage the situation and make use of the early morning time in the parks.
Good luck! Maybe I'll see you among the crowds down there this Christmas.
