I thought that this episode was pretty good. I wasn't expecting a brief time skip, but given everything that happened during this season, giving the characters a bit of a break made sense. Historia helping kids from the underground was nice, although it's strange that I don't remember that plot detail before they covered Kenny's backstory. They made some progress with Eren's training and making more weapons against the Titans too. Even though it has only been a few months in-universe, the group has been through a lot compared to some of the other newer recruits, especially when they had to kill other people recently.
I wasn't expecting them to bring back Keith, but they needed someone to provide a bit of insight into Eren's father. Since Eren's father had no memory other than his name and occupation, I wonder if he had some run in with the Reiss family and somehow got away from them. That could explain why he confronted them and gave the Titan powers to Eren later on. While it was sudden to bring Keith back, he did work as a mirror to Eren. They both thought that they'd be the extra special person to help save humanity, but they both felt like they ultimately caused more innocent people to die as a result of their actions. Eren's mother saying how she just wanted him to be himself instead of being special was at least a sweet notion and provided a bit of comfort to Eren as he keeps trying to live. Overall, it was a pretty good episode.