A lot of people think that Old Legends from the previous era like Garp, Sengoku, Rayleigh are on the same level as current Admirals and stronger than current Admirals when they were in their prime.
But I think that would really undercut Luffy’s achievements of becoming Pirate King if all the current Admirals aren’t as strong as the previous generation in their prime.
In the next era when Luffy is Pirate King I’m sure someone like Akainu will be viewed in the same respect as Garp is in the current era. What people will know is that he killed the brother of the Pirate King before his eyes and made him flee for his life.
So actions in the past are always viewed how it happened in that moment. We will know that at the end Luffy will probably beat Akainu, but the other events still happened. So now look what we know about Garp.
He got the distinction of “Hero of the Marines” from dealing with Rocks, a group of people who were prominent 40 years ago before the Pirate King Gol D. Roger came into power.
He is known for cornering and fighting Gol D. Roger many times. Roger also stated that he and Garp had almost killed each other on numerous occasions.
I think that the strongest characters of the current generation will be at the same level of the Legends from the past generation in their prime, if not, Luffy becoming Pirate King will be less impressive than when Roger became it.
*Theory by KayWWW