Hi Tiffany,
I'm assuming that you are definitely going to the Magic Kingdom, since it is not to be missed with a toddler. In response to your question, I personally would choose Animal Kingdom (AK) over Hollywood Studios (HS) every time for a 2 year old. Here's why:
Hollywood Studio's does have
Disney Junior Live on Stage which your toddler will enjoy. Beyond that, there are a lot of shows which are hard for a little one to sit still in. There are also rides with height requirements. My older children consider HS to be their favorite Park (because of the thrill rides). However, for toddlers, the options are not plentiful. I'll always remember when I asked my youngest (then barely 3) if she had fun at the end of a HS day. She said, "No, me don't like food". It was then that I realized that while all of the other kids had enjoyed the thrill rides and shows, the only thing she was really able to do was eat. She did watch The Voyage of the Little Mermaid and Beauty and the Beast, but apparently they didn't leave the same impression on her as other Parks. Now, at 6, she absolutely loves HS and all of the shows.
Animal Kingdom on the other hand, has countless attractions for toddlers. Your whole family will enjoy the
Kilimanjaro Safari, the Pangani Forest Exploration Trail, the Maharajah Jungle Trek, the
Affection Section and much, much more. My entire family thoroughly enjoys the Animal Kingdom. Most toddlers love animals and I think your 2 year old would make many memories there. My little girl talked about the hippos and zebras for months after-wards.
Have a wonderful vacation,
Kaylene