Blame Scott Buck. All the reviewers so far seem to blame him for everything that went wrong. And Jeph Loeb saw his work and then hired him for a second TV series. And it isn't like Defenders where it shoots when Daredevil isn't. This is giving Scott Buck twice the workload so he can ruin another Marvel franchise.
Here's the thing. Iron Fist was always a hard sell. The character is seeped in Orientalism and cultural appropriation no matter what you do with him since he represents an American take on Chinese culture. (The fact that a major character is named Lei-Kung instead of Kung-Lei when Kung is a Chinese surname and Chinese names put the surname name first and given name second tells you all you have to know when Marvel butchering Chinese culture. To be fair to Marvel, they were even worse with Russians.) If you cast a white guy, you wind up with the Mighty Whitey trope. If you cast an Asian guy, you run into some seriously uncomfortable stereotyping.
But even with the cultural baggage of the character, Marvel still could have done an amazing series if they actually had a competent showrunner. Instead, they picked the absolute worst person they could find who mismanaged everything at every level... and then made him the most powerful showrunner at Marvel Studios. He stopped the Defenders momentum right when it seemed unstoppable and now seems be doing the same to the cosmic side of Marvel right between Guardians 2 and Infinity War.
Most importantly, Scott Buck seemed to be embarrassed by the source material. He was literally so scared to make a wuxia series, that he created an office drama instead. No costume. No wirework. No connections to other properties aside from Claire Temple.
There was no way to make a culturally sensitive Iron Fist, but the oft described scene where Danny tells Colleen that her Mandarin is wrong seems like Scott Buck and company wanted to play up how dated the concept is. When handed the title, Chris Claremont worked hard to make Iron Fist less offensive and the Brubaker/Fraction team doubled down on trying to to make an Iron Fist that wouldn't alienate the audience. Iron Fist can be done well, but Scott Buck decided to do everything possible to make audiences hate an already divisive character.
So I won't be watching Inhumans. I know that it's going to be a trainwreck. Scott Buck is no David E. Kelly. He's the Antichrist of the TV world who's now ready to take the MCU down with him. No wonder this guy doesn't have a Twitter account.