Your answer is dependent upon how much you care about where you stay. If you book now, you'll guarantee yourself a room you like. If you wait for potential discounts, you may be locked out of your #1 location. If you don't really care (for instance, if your plans are to stay at "one of the values" or you don't care if your room overlooks a parking lot) you can probably afford to wait.
F&WF is a popular time to go, but it's not like Disney is going to fill up. It might be harder to find a good room at the Beach Club or other EPCOT resorts, but its not like you'd have to cancel your trip.