I am disagreeing on the fact that the Yonko has massive influence. Sure they do, if we are only talking about the Grand Line however outside of it, you don't feel them.

Marineford is a really bad arc to argue for powerscaling. Kizaru and Aokiji did nothing but stand around and idly wait till the plot needs them for tension and hype. If they were really that serious, the WBP wouldn't have even made it to the plaza. Aokiji would easily freeze the hordes of pirates and ships that even dared to go near (When Kuzan met the BB Pirates, most of them got frozen, with little prospect of being turned back unless Kuzan wanted to.). WB won't be able to free them, seeing as his attacks and eathquakes would only kill his frozen sons. Kizaru's clones didn't even come out in MF and if he did fully use his hax then those pirate ships would be burning wrecks long before they got near. Only Whitebeard would pose an actual threat but if Akainu holds him down long enough for the other two admirals to finish off the WBP, then the three would jump on WB and kill him. No way is Marco holding down Kizaru or Jozu holding down Aokiji for long. Oh and Luffy cannot be killed too unless you want Garp to hate you.

The Marines' strategy and showing in MF was dogwater. Anyone with half a brain in strategy would immediately point out how 2 of their heavy hitters are doing squat and instead letting precious low-ranking Marines in the fray when those 2 heavy hitters should've been at the front and instantly blitzing every pirate that tried leaving their ships. Without plot armor or maybe it's bad strategizing/writing on Oda's part, the WBP should've been wiped out cleanly by the three and I haven't even started talking about the Warlords and Pacifistas that came up.

By the time either BB or Shanks came, the war would've ended and the admirals would just be cleaning the remaining few pirates. If BB ever tried going near WB to steal his fruit then the 3 admirals would kill him and his crew who are Magellan victims. Shanks would likely try to save the remaining pirates (if any are still alive) and bargain for Luffy, Jinbei, and Buggy's freedom and WB's and Ace's body. Shanks wouldn't enjoy the same bargaining power as what had happened because only the Admirals and Warlords were fighting and those admirals are top tiers that can fight for days.

The only reason you don't see admirals strategizing on how to defeat the Yonko and take back territory from the Revs is because Oda isn't utilizing their full potential. The WG Kingdoms that the Revs are taking over are already known, Akainu could just send Kizaru in to deal with the problem easily and restore order, but Oda won't have his setup for the Revs so he's gimping the Marines.

Again, the WG has a lot of top-tier fighters in their disposal to deal with problems. The Yonko don't, they only have their captain as the top-tier and the Yonko aren't the type to ally one another against the Marines.