If they wrap the series up with a big conclusion... a final fight against Genesis that resolves all of Shinra's many plots and schemes, and settles all the corruption of life that the company produced, then it could be a good way to go out. If they could produce an RPG that rivals the depth and scope of the original FFVII, and expands on the world that already exists without trying to re-write any more of its history, then it might just work. It'd need to be something that ties up the loose ends - like the full back-story behind Shinra's secret human experiments - without being hopelessly convoluted.
It'd need to be a game that's good on its own merits, though - not just an exercise in pretentious "omg look at me I'm an FFVII sequel, respect yo".