While I sort of agree, the thing is that Netflix controls the episode count and stuff. It's not a movie, no theater run time, it's not a tv series that has to fluff 23 episodes out with winter breaks and stuff.
Almost everyone that watches them will do so within a one month subscription time. If you are subbing JUST for this show, it doesn't matter if it's 9 episodes or 13 or 20.
I mean, it's the perfect format for a writer/ director to tell his story over his required time frame, why come up with even more arbitrary rules?