I don't see how losing backwards compatibility would be a good thing per se. Even if the preprocessor were considered a problem (which is disputed), it could co

I don't see how losing backwards compatibility would be a good thing per se. Even if the preprocessor were considered a problem (which is disputed), it could coexist with a new FFI system that could be implemented. Losing backwards compatibility is usually a price to pay, not an objective. As an example, Python 3k chose to lose partial compatibility to 2.7 in order to change some parts of the language. While the user and maintainer community still debates if the change itself was a good decision (a different discussion IMO...), probably most will agree that the incompatibility bit has been and will be for some time a source of pain.