Hi there-
My youngest was just barely 1 when we went back in January and she had a really good time. She enjoyed several of the rides including the Winnie the Pooh ride, Small World, Peter Pan, Dumbo. We even took her on Pirates! She liked watching many of the shows and parades. She really liked meeting the characters (especially the Pooh gang at Crystal Palace) but I've heard some kids are afraid of the characters, so take that slow. She also enjoyed the playground and fountain areas, so plan some chill out time, settle yourself on a bench with a cool drink and watch your little one play at Donald's Boat in Toontown or the Pooh Play area...or any of the other playgrounds. They do get wet though, so bring at least one change of clothes.
We took our own stroller and packed it with small drinks and snacks we knew she liked. The snacks were a good diversion if we got stuck in a line. I would suggest avoiding lines if at all possible. Get fastpasses, or go really early in the morning and take an afternoon break, because even the most even tempered toddler is going to get cranky waiting in a line for 30 minutes. We also had our car with us and we often drove to the parks. I know a lot of people like to have a driving free vacation, but we tried to avoid crowded buses with our tired kids when possible.
Trust you instincts though since you know your child best. My DD is very laid back and can snatch a good nap in the stroller. Kids who really need to have a routine to unwind at home might need the same at WDW, so many parents go back to the hotel for an afternoon break/nap and try to keep the same bedtime/mealtimes. All of the parks have parent-child comfort stations with comfy chairs where you can nurse or prepare a bottle. They are usually located near the front/gate area. We only used them a couple of times, but they seem to be cheerful and comfortable.
You will have a great time. If you have any specific questions feel free to PM me.