Might just be that the Superman story is kind of done at this point in every form imaginable hence they want to do a more Clark Kent story with a superman added to it.
A Clark story would also be cheaper to produce then a Superman story and this would give the creators a bit more flexibility in terms of story compared to the villain of the week format.
I personally would love to see a healthy mix between Clark Kent the dad trying to teach his kids the journey to becoming Superman while at the same time Superman saving the world.