I give the show a 5. That's probably pretty generous considering just how flawed this series is. Overall, the show is not very good -- much of the story is poorly conceived and poorly executed. The basic plot concept is good and solid, but the execution is frustratingly shortsighted and uninteresting.
I like most of the actors, and I think they're trying as hard as they can to make the show work. The problem is that the scripts don't give them a lot of good stuff to work with. In too many episodes, the script fails to build interest and excitement. Instead, it just slogs along from one scene to another, pointing out things that are happening. When I watch something, I want to feel sucked into the story so that every scene leaves me intrigued about what is going on and excited about what's going to happen next. Unfortunately, this only happened sporadically, at best, for me when I watched this show.
Since I'm a Marvel comics fan, I did enjoy picking out various Marvel Easter eggs and various references to Inhuman lore from the comics. However, this wasn't enough to make the storylines interesting. The biggest problems came during the episodes when the Inhuman royal family members were all separated from each other on Earth. This was a big mistake by the writers because it robbed the Inhuman characters of opportunities to interact more with each other, and thus make me more interested in them as characters. Also, most of the human characters they met on Earth were so dull.
It was also very disappointing that we only got ONE episode in the entire season where Medusa got to do cool stuff with her hair. Then her hair was all shaved away towards the end of the VERY FIRST episode, and she essentially had no Inhuman powers at all for the rest of the season. I was hoping that Medusa would somehow get her hair back in the season finale, but no such luck.
I loved Lockjaw whenever he was onscreen, and the members of the Inhuman royal family had some occasional good moments and good scenes. But overall, it was difficult to grow attached to them because the scripts didn't make a huge effort to make them understandable or multidimensional as characters.
Since I'm a Marvel fan, I'm still glad that I watched the series for the good elements that were to be found among all the bad elements. But the show is still a big disappointment because it's definitely not up to Marvel's usual high standards.