IMO, I think that it is really "counting your chickens before they are hatched" to wonder what sorts of things might be done for your anniversary at your WDW resort. My husband and I have been at WDW for several different life events (including our Fairy Tale Wedding and anniversaries) - and sometimes, the resorts will make a big deal out of it, sometimes they won't recognize the event at all. It all depends on how busy they are, what CMs are working, and LUCK!!! If you REALLY want to make sure that your anniversary is recognized by something special, make sure YOU take care of the plans yourself - a special meal, flowers sent to your resort room, a "gifts of a lifetime" event (if you are willing to splurge!!)... Maybe you will get something extra from your resort/restaurant PS's as well, but if you don't, at least you will have taken matters into your own hands!!
By the way - we are leaving for our anniversary trip (Poly) in a few days - I will let you know if the CMs there do anything special for us...but in the meantime, we have flowers coming to our room - and I am hoping to book a Gifts of a Lifetime event as well!!
Happy Anniversary, in advance!