Much ado about Hardshell has been made, and I wanted to spell out my thoughts about it in a manner that wouldn't get lost in a sea of posts. "Hurt" is about revenge. Specifically, how revenge is hollow and doesn't ultimately achieve anything. This was a lesson Miko had to learn, and if Hardshell hadn't died, it would have been much more hollow. Much ado about revenge as a character point has been made regarding Arcee, and the distinct difference between her actions and Miko's in this episode was that "Hurt" had to explore what happened when someone achieved it. This is shown when Miko says that she "doesn't feel different" even after she succeeded in killing Hardshell. Hardshell had to die, because Miko had to do something she couldn't take back. How "cool" he is is not the point. Much ado was made about how much potential he had, but that's not why Hardshell exists - Hardshell is an example of a character being used as a device. This is a perfectly valid approach to storytelling as much as any other. If nothing had happened, if Miko had NOT been the one responsible, this episode would have no teeth at all.