Yeah, tagging along with Shamrock would give some form of threat lvl.
I assume there are at least 9Holy Knights, adding over 10-20CP0 members, that is actually a strong force.
Still don´t know why the WG really needs the Shichibukai, having CP0 and Holy knights together with the Navy is enough to deal with any yonkou/pirate.
The World Government exists
primarily to ensure the secrecy of Mu and the Void Century. The WG exists secondarily to protect the Celestial Dragons, and they have tertiary issues like exterminating the D race.
Keeping the order by installing pirates in key places under the WG banner is a great idea. Beating pirates and creating a utopian society is not their goal. Keeping the world disorganized and afraid is part of achieving their real goal of secrecy and immortality.
This translates directly into their approach with the God’s Knights, who work to undermine and infiltrate prominent factions (Revolutionary Army) or destroy the reputations of prominent individuals (Shanks). These knights are wearing disguises to pose as their enemies to keep the factions working against each other through misinformation. Just like the shadowy cabal in the real world.
We will see this play out soon.