i rather call star wars episode 2 a galaxy divided i don,t care if the clone war series has the name, it's an expanded universe and as adywan has said, it doesn't exist in the movie cannon.

the name works better than attack of the clones because like the titles from the OT, it sums up what is happening in the movie.

episode 1 does need a new title as well but i'd leave the episode 3 one the way it is. not only because the title feels OTish and sums up the movie, it is also my favorite title out of all the prequels