Overall I really enjoyed the season, especially after episode 5/6 when they dropped the unnecessary, over-the-top violence. I thought the first five episodes, full of our hero torturing people and upclose shots of compound fractures bursting through the skin, felt like they needed to justify the TV-MA rating a bit much. Once they backed off of that, the show improved greatly. I loved the Kingpin, especially the subtle Norman Bates-y qualities he has. Madame Gao is clearly a set up to payoff in the Iron Fist series.
I'm not a fan of a late death that I won't spoil here. But the character should not have been killed.
The bigger problem for me tho: this should have taken a page from Agent Carter and been a 70s period piece. A kid listening to boxing on the radio, a crusading newspaper reporter, heroin trafficking--they all feel dated, even anachronistic, in 2015. Even "Hell's Kitchen" feels out of place--the neighborhood's pretty gentrified now, not the evil pre-Guiliani NYC the show wants it to be. At one point even the soundtrack felt 70s. Had they set this decades earlier, it would have been a fun romp that could name-check SHIELD. Instead, I saw too many tropes from the 60s-80s comic that should have been updated--it feels like the equivalent of Tony Stark still being a POW in 'Nam. while largely avoided current events in the MCU.
I think they don't do enough to show that the reason the city, and Hell's Kitchen, are in disarray is because of the events of The Avengers. They make passing, vague mentions of it, but we really needed to SEE what happened to the area after the Battle of New York. Granted, this isn't our universe, and I see no reason why in the MCU Hell's Kitchen couldn't still be a crap hole, but since they used the Chitauri Invasion as the reason for its hard times, they did a really bad job showing it. I have to assume that's due to it having a TV budget, but still.
Overall I thought the series was good, but flawed. I wouldn't rank it above The Flash or Arrow on the CW, but it's infinitely better than SHIELD or Agent Carter, both of which I find fairly boring. In the MCU, it's better than the Thor movies and Hulk, but I'm not sure I'd rank it above anything else.