When the split cards were created in Invasion, one thing everyone knew was necessary to pull them off was catchy names -- phrases made of words that meant something individually, yet still made sense together. Spite/Malice is a good example -- I can counter your spell out of Spite, and kill your creature out of Malice. And together, "spite and malice" is a relatively well-known phrase, and is even the name of a card game played with normal playing cards.
At least two of the original five split cards went through name changes. Assault/Battery was originally known as "Hit/Run". While "Hit" is passable for a direct damage spell, "Run" is pretty silly for a token generating spell. Plus the name refers to a type of automobile accident, which isn't the best source of material. Assault/Battery is definitely the better name.
Wax/Wane's first name was "Pride/Prejudice". While those terms might make more sense -- Pride makes my creature stronger, and Prejudice makes me want to destroy your enchantments -- some members of the naming team didn't like the fact that the name was taken from a novel, Pride and Prejudice by Jane Austin.