I like Individual's analysis, but prefer it to remain the first two options, not the last three.
There should not be any new 'branches' set-up. It sounds too schismatic. Fortunately we don't have any Pope or Vatican in Buddhism, so there can be some minor differences of opinion and we can all still be Theravadins. Even among Classical Theravadins or Modern Theravadins, just as in any married couple, there are going to be differences of opinion. I don't know if there are any two people in the world who agree on every issue and have the exact same stand on every issue. Maybe there is, but I have not seen it.
Therefore, the minor differences are just that, no need for new branches, schools, or sects (within Theravada).