The French did try to introduce a romanized version of Khmer, but it coincided with the independence movement and wasn't welcomed. Norodom Sihanouk railed against it, and the whole idea was abandoned. It's not easy to romanize a language that has many sounds that aren't normally heard in western languages. However, I do feel that the Khmer script needs to be simplified, and one of the main reasons that Cambodians don't read much is because of their over-complicated script.