I actually liked the contrast gorosei had with the standard CD, who were spoiled scumbags, while they had a nuanced, wise king type energy back in the days. Even during their intro in Ohara, while stern, they also had a more diplomatic side. They even tried to give an out for the researchers, and preferred evacuating the civilians.
They were repeatedly shown preferring stability and minimizing casualties. Even when Imu asked them to test mother flame on Lulucia, they would've rather used it on sea, and expressed concern towards civilian casualties, before being bullied into submission by Imu.
Oda had written Gorosei with more nuance than fodder CDs, as he usually do for many of his villains (Arlong, Doflamingo, Kaido, Moria). While they are to be seen as bad guys, there is more to them than meets the eyes.
I had initially speculated Gorosei to be 5 amongst the OG 20 kings.
But in Egghead, Oda threw it all out of the window. Made them straight up behave similar to trash like Charlos. Had Saturn kill marines and even some vice admirals. Made them effectively slaves of Imu, who are the source of their immortality.