And it would still have to travel a ways to get to Regula. Or did you forget that while the nebula is visible from Regula, the planet was not visible from as close to the Nebula as they were before going in.
Oh and as for
It doesn't introduce some new properties of Genesis, that were never stated in the movie anyway.
They never said the wave could magically fly through space to find a planet to change, where as they said it could change an equal mass into living mater which in making a planet is a bit of a stretch but still possibly with in the abilities of the device. One (your point) is something that goes against how the device was shown to operate while another (not your point) is a stretch of an established ability of the device.