Shunshinkun’s death taught me one important thing
Shunshinkun’s death reveals that generals and leaders live with and amongst death, dead and the dying. And what makes a person a great leader is one who can fight competently against external and internal threats.
Accepting Rien into his circle and then letting his sister effectively give Rien all the handles to power was a lethal mistake. In a world where death and dismissals hurt the overall performance of a character, even a great general of Renpa’s persuasion should and must be wary of the court.
In contrast to Tou, who knew had no opposition in court and so was able to successfully conquer Han and then retire safely and happily; Shunshinkun was decidedly the exact opposite case. The man was powerful enough that his eminence became a weakness. The best leaders and generals should be expected to know how to accommodate that, be it planning around it or being absolutely nice to the court. In a sense, Renpa and Shunshinkun are the case studies for why being too strong makes you not as great of a person.
There’s a common saying “by making someone good, you failed to make them great” Shunshinkun’s strength essentially hampered his ultimate ability to be the greatest man of Chu’s history. And for Renpa, at least he survived although his sacking does stain his reputation quite significantly.
TLDR; Shunshinkun could have been awesome if he just killed Rien after the king died without any hesitation.