Okay, so I loved the Divergent series. My favorite books in the world. But this book just about killed me. Tobias loves Tris, not Christina. I know Tobias would want to move on, but not by dating Tris's best friend. It was all just wrong. This is not how they would all act after losing someone as dear and special as Tris.
If I wrote the books, I would still make Tris die from serious injuries, but she would be in the hospital for like a year in a half first, and what kills her is giving birth to her and Tobias's child since she was already severely injured. Tobias does heal over time, but what heals him is not another love interest, but his daughter.
Meanwhile, Christina acts as an aunt figure in Tobias and Tris's child's life and she also falls in love with Peter after he reinvents himself since he used the memory serum. Caleb and Cara also end up together and live happily alongside Caleb's neice.
The world is still broken and they have all lost someone they love, but they mend together and help each other to create a beautiful life.