Victoria and Albert's is always a nice splurge.
If you do California Grill get a seating at sunset and watch the sun drop over the lake. Also ask for the wine room. It is a special section reserved for small intimate parties, tell them it is your second honeymoon and you should get a table. The room has spectacular views, is separated from bustle of the main dining area, and is where the most attentive servers work. It is a special experience.
The Polynesian beach during Wishes is always a winner.
In December a drink in front of the Wilderness Lodge fireplace is spectacular.
Narcoosssee's is one of the best kept secrets on the property and can be exceptionally romantic.
Make sure you get your celebrating buttons at the resort or guest services at the parks.
Check out this thread,
http://forums.wdwmagic.com/showthread.php?t=550005&highlight=romantic, on WDW's most romantic spots. Dozens of great posts there.
Talk to the concierge at your resort before you go down, they have all kinds of special in room packages they can put together. Chocolates, flowers, and champagne are the standards, but there is room for creativity. There is a premium for those types of services, but a once in a lifetime experience may be worth it.
You can also have things shipped to your resort ahead of time. For my wedding I went to overstock.com and had a gross of long stemmed roses and bags of rose petals shipped to my resort. I went to the dollar store and bought a ton of cheap glassware and candles and had them sent ahead. Being it was the wedding I friends along and one of them set it all up while we were out, but you might be able to find a CM willing to help with something like that for a nice tip. I'd call a few weeks ahead of time and chat-up a concierge and see if they are willing to help you out.
One last tip, be sure to tell every place you check in how special the vacation is for you. There are no guarantees, but when I returned for a combined first anniversary, DW's birthday, and last hurrah before deploying trip I asked for a nice table at the Crystal Palace and when Pooh came around he brought my DW a snow globe as a birthday present. They never mentioned it before hand and nothing was on my bill.
I was told later that most venues get surplus merchandise to create those magical moments. I wouldn't go looking for it, the CM's can sniff that out, but casually talk about how important this trip is because you missed your real honeymoon and see what happens.
Good luck.
it just makes it a little extra special when people wish you well.