Chicago Fire - Season 4

Note: This is my first firefighter show. Also I'm not from US and binge watched the show till season 9 recently. So my opinion might be different from people who watched the show in original air. The first three seasons were focusing on the fire fighting more than the relationship between the characters and I really liked it. I've even cried in some episodes for the sacrifice and help firefighters do to the community. A Coffin That Small is one of the episodes. I liked Herrmann's character for his principles, how he was strong with it even though the situations are difficult and how Cindy was supportive to Herrmann in all those situations. I missed them in the later seasons. The next seasons were not good as the first three as they start focusing on the relationships between the characters (The balance was good though). And I did not like Gabby's character during these seasons. I know Casey had his problems but still Gabby's character was not likeable. The relationship was very much one sided (not in the first three seasons). Casey always tried to support Gabby but did not got the same from Gabby sometimes. I did not hate Gabby, just not liked the character much as other characters in these seasons. I liked Mouch-Trudy whenever they were on-screen. No hate, but I really didn't get Kidd-Severide relationship even in the later seasons. I always felt Kidd's character was written in the way to focus specific target audience. I might be wrong, It's just my perception. The next three seasons were really good in focusing relationship more than firefighting. I loved Brettsey in the these seasons. This relationship was always two ways and Casey was happy always even when they had a break in season 9. Otis's death was impactfull for first few episodes but not later. I felt Otis's character was under-utilised in the previous seasons after his death. I liked Cruz-Chloe relationship. I stopped watching after season 9 since I read the spoiler that Jesse left the show. But I watched the Brettsey via this [playlist](https://www.youtube.com/watch?v=9MwfKnuIHyA&list=PLPh06C6rTjH8LwuTRjY5q46lm5L8VQgA9). I tried to watch season 13 (skipping season 10-12) as it looked like a fresh start with new chief, new paramedics and Severide having a brother. I feel the show changed much after season 9. Is it due to the show runner change, I read it somewhere.