I can see what you're trying there, and it could be a good idea once fully developed and tested for every country, but as of now, it's what I feel is making me not want to play the game any more.
Not being able to finish the 1949 NF tree is very annoying. The way the currently on-going NF just gets discarded is terrible. But worst of all is the generic NF you get once you reach 1960.
If you really intend to keep this method, then please disable the NF-switching for nations that don't have a 1960 NF