You want me to make a list of all the characters that have embodied the oppression of the WG? Kuma is not unique in that at all. So tell me all the attention he gets now, what was important in it? What have we learned in this long backstory of Kuma that is "important"?
None come close to Kuma, he’s had deep ties to the story from the beginning
Pre TS what have we learned
-Ruthless warlord who obeys the WG
-Found it in his heart to accept Zoro’s sacrifice
-Acquainted with Dragon
-Saved the SHs
-Turned into a fully blown machine
-Used as prototype to clone weapons of mass destruction
-Introduced Vegapunk
Countless mysteries regarding his character that need addressing
He’s not just some character that sprung out of nowhere
Quoting myself:
From a clueless little boy who lost his parents, to a priest living a somewhat normal life, then his work as a revolutionary eager to take down the WG, raising his tragic friend's daughter, then being branded as a tyrant and forced to join the Warlord roster, and being forced to become a human machine that ruthlessly obeys the commands of those who detests most so he can save the one he loves most, only to end up as a complete machine devoid of consciousness all while being cloned to become the new face of weapons of mass destruction.
His story is literally the embodiment of the World Government's 800 years of tyranny.
It is so merciless and cruel that a saint like Kuma was bent and twisted terribly enough that he ended up having no remorse about killing his best friend's son (if not for Zoro’s sacrifice that moved him)