Even though this song is meant to compliment "One Girl in All the World", I don't think that makes it necessary to compare them to each other in a sense of which one is better. Both are fantastic - each just puts its own spin on things. They have different focuses - while "One Girl in All the World" seems to focus on the feeling of one girl isolated in a vaste unknown place, giving a lonely undertone, "All the World in One Girl" is more introspective. It shows an underlying, simple happiness and beauty. It's cheerful, but not obnoxiously so. The piano is light and intricate, flowing beautifully throughout the piece, and the organ is a lovely, lively addition that suits the song well. There seems to be quite a variety of instruments that are perfectly blended together. The drums don't do much, but they're subtle and carry the piece without "intruding", so I haven't a problem with them.
I initially heard this one right after listening to "One Girl in All the World" and at first didn't like it as much. But after a few listens, it felt to me that "One Girl in All the World" was meant to carry a feeling of exploration, power and loneliness, and "All the World in One Girl" was of a more inward, thoughtful, comforting and simply happy focus. They're two different looks at one thing, which is what remixing in general focuses on - a different take on something. The feel of one might appeal to some more than others, but both pieces are excellent in their own right and each compliments the other perfectly.