how do you reckon this? Sugar's fruit is supposed to make everyone forget the missing people ever existed. We even got a hint of it when the marines were reading the names of the colosseum participants and they couldn't recognize some names.
Well it makes you forget who is missing, but I wanted to say that he knows that SOMEONE is missing. But I remember when Fujitora told one of his subordinates to find out how many people lived in dressrosa? Seemed random to me at first, but I think a list of all inhabitants of dressrosa would only make sense if fujitora has a clue that people are disappearing.
They're more trouble than they're worth. Doflamingo is actively undermining the world government through his underground operations, Mihawk doesn't give two shits about anything. Law used it to get on Punk Hazard and blackmailed one of the others to defect from the system, essentially poking holes in that very system. Hancock hates everyone and won't hesitate to attack indiscriminately when they request anything of her. Buggy is probably off somewhere hunting for treasure with Alvida. The only straightforward useful guy they have is Kuma and they made a shit ton of clones of him. It's not like anything is stopping the marines now but removing the system would change nothing for them. The disadvantages fall towards the few shichibukai who actually need the position for safe havens (this mainly applies to Hancock and Buggy). The Marines don't lose an ounce of strength on their side, and with the conscription, any possibility of them facing a severe shortage of fighting force while dealing with the Yonko or the Revolutionaries is probably negated. Also none of these fuckers would help the Marines anyway.
They dont loose strenght, but they gain enemies: The schichibukai and the pirates that would have been defeated by the schichibukai. I mean Marineford didnt make the marines stronger… They lost garp, sengoku and aokiji. I sometimes wonder why the new admirals havent been at the war or if they have been but we dont know. However destroying the schichibukai system seems like a overconfident move, considering there are guys like blackbeard, shanks and dragon out there. And while you are right that noone of them was a particular big advantage for the marines, having to face them in the grand line seems like an additional task they would have to manage.
If the marines want to risk the stability of the world and take down one of the three big powers, why not start with the yonkos (of course they cant just destroy all the yonkos but slowly trying to stop them since like a better idea than attacking pirates that arent a danger for the marines anymore).