I don't mind the Inhumans, but it's the 21st century, and it's not gonna fly to make a story about a bunch of anti-democratic white monarchist eugenicists who live in their own little enclave with a caste of slaves doing their scut-work.
They've gotten rid of the slaves (back in the 80s), and tried to use the T-mists and introduction of new cities like Utolan and characters like Jiaying to open the concept up to other ethnicities, but there was a lot of stuff to jettison, and it was not handled well (pitting them against mutants by retconning Terrigen mists, which previously were fatal to humans but totally harmless to mutants to suddenly be harmless to humans and fatal to mutants? So dumb.).
Plus the main characters in a city of thousands of super-folk being the royal family was inherently limiting, IMO. Spider-Man can go anywhere and do anything. But Black Panther's a king. Running Wakanda might take a minute. So it doesn't make sense for him to be off on every single adventure, like he's got unlimited day passes excusing him from his duties as king. Same with the Inhuman royals. (All though it is consistent with how much crap happens to Attilan that the people in charge are never actually around to do their jobs, I guess. Same with Atlantis being destroyed once a decade when Namor's off Defendering or whatever.)
Given the nature of the Celestial tinkering with the human genes to create mutants, and how the Terrigenesis process designed by the Kree doesn't actually work on the Kree, who lack that Celestial-granted potential for the mutation, it would make total consistent sense for 'activated' Inhumans to detect as mutants, since, for all purpose, they are. (If not all actual 'mutants' from birth, although some, like Black Bolt, are that too, the ones activated by later exposure to the Mist as teens would at least be 'mutates' like Vertigo of the Marauders/Savage Land Mutates, created by Magneto.) That would certainly be a hoot, for the Inhumans to be belatedly discovered to be a city teeming with mutants, some full active mutants, many 'triggered' into full mutant status by the Terrigen process, and they didn't 'detect as mutants' for so long due to some other factor, making the whole division utterly meaningless...