Unlike the previous episode, #9.21 has a coherent, well-integrated story. The red-herring flows naturally from the initial crime, and doesn't feel tacked on (or invented out of thin air). The clues are fairly subtle, but point to an accurate portrait of the unsub. This is how profiling (the central theme of the series) is supposed to work. The only ding I'd give the plot on technical grounds is the use of "Injustice Collector" in the profile. Injustice collectors from my understanding essentially shift the blame for their actions, woes and shortcomings to anything/everything else handy, and away from themselves. It's a combination of paranoia and irresponsibility. Christopher Dorner is mentioned by name, but Bryce Williams/Vester Flanagan (Virginia on-air shooter) is another example, one that occurred after this episode aired. The unsub in this episode is motivated more by straight vengeance borne of guilt/survivor's guilt. An actual injustice collector would be an excellent topic for a future episode (hint, hint).
The portions filling out Derek's love life in the B plot are obviously written by a woman (the womens' dialogue is stronger than Derek's, and wouldn't sound out of place on The View, or an old episode of Ophrah), but if the women writers keep coming up with tight, strong scripts like this, then I say keep hiring them to write more. I'm a guy, but I can sit through a few minutes of Ophrah-speak to get to the rest of this story's substance.
The portions filling out Derek's love life in the B plot are obviously written by a woman (the womens' dialogue is stronger than Derek's, and wouldn't sound out of place on The View, or an old episode of Ophrah), but if the women writers keep coming up with tight, strong scripts like this, then I say keep hiring them to write more. I'm a guy, but I can sit through a few minutes of Ophrah-speak to get to the rest of this story's substance.