City of Glass had a lot of great things going for it. There was lots of great character development, battles, and intriguing events. 
 However, my main bone to pick remains- predictability. Although, there was finally one thing that happened that I only half guessed, so that was a relief. Took three books, but it was nice to be surprised, even if it was only somewhat, and only one plot "twist". 
 While City of Glass upped the game and was better than the previous two in the series, there were a few new problems that happened that kept it from reaching it's highest potential. 
 1. Death: Not a plot device/What is dead should stay dead- (view spoiler)[ It's book three, and it's time for some serious fighting. While in the previous books, there were some battles ranging in size. Sure, a few deaths happened, but it was no one we cared for. Now, with the war Valentine promised, you would think there would be more causalities other than background characters. There was only one semi real loss in the book- Max. I felt bad for his family chars, but at the same time I was really distant from his death because he was still a background character, and because his death was not meaningful in any way. Instead, it was a plot device, which cheapened his death. On top of his death, I have to say I am frustrated at this point in the series that what's dead doesn't stay dead. Simon has "died" and came back in a previous book. Jace dies in this one, but comes back. While I really enjoy these characters, and don't WANT them to die, I want the things that die to stay that way. Constantly killing characters, and bringing them back makes me numb to their deaths because I expect a resurrection. It cheapens their sacrifice, it cheapens their death, and overall it hurts the book because I become detached to character deaths. (hide spoiler)] 
 2. Hooking up/Relationships: Not everyone needs to be paired up. (view spoiler)[ It is the middle of a war. Not everyone is going to get closer during perilous times. All the main characters get connected together at some point, and it is unnecessary, messy, and complicated. I felt like Clare kept mixing random characters together for the fun of it, creating not a love triangle but a romantic catastrophe, just to mix things up. The relationships throughout the series so far feels more like something that belongs in a daytime soap, rather than the middle of a paranormal war between life, death and slavery. (hide spoiler)] 
 3. Build up: Multiple chapters of build up, anticipating a major fight...that kind of falls flat- (view spoiler)[ This one ties in a bit with the first one, but on top of the whole "it's war and none of the main characters died", there was so much build up for a fight that was divided in two places. The overall main battle lasted no more than ten minutes, and we barely saw any of it. The 'secret on the side' battle between Valentine/Jace-Clary was incredibly anticlimactic. The battle between Jace-Isabelle/Jonathan was much more interesting. (hide spoiler)] 
 City of Glass had a lot of great moments that improved my outlook on the series so far, but it still just hasn't reached a point where I want to hold the book up like Rafiki and praise it to everyone in the world. It was pretty good but it still just doesn't seem to reach 4 star status. Overall, City of Glass gets an awkward 3.9 stars.