It would work, but it's a little more complicated than necessary.
Plus, you would be pre-assigning the space for games, documents, and media. So you could run out of room for one while you have plenty of space for another. It might make more sense to have one data partition with different root directories for games, media, and other.
Oh, by the way: Back up early, and back up often. Otherwise, a hardware failure can make your partitioning irrelevant.