Lmfao.
Yeah Viz murdered the Rayleigh ~ Gaban notion with that change, there's clearly a hierarchy (which is obvious anyways as Gold > Silver > Copper).
The shoulder to shoulder line really isn't that deep - the amount of characters you can say stood shoulder to shoulder together yet were lightyears apart in terms of strength is crazy.
As you've said, Oda himself stated Arlong stood shoulder to shoulder with Jinbe and Buggy stood shoulder to shoulder with Shanks.
The rooftop 5 stood shoulder to shoulder together vs the 2 Yonko, Oden stood shoulder to shoulder with Whitebeard, Sakura stood shoulder to shoulder with Naruto and Sasuke lmao. You can say the same for the three calamities, for the 4 sweet commanders incl. Snack, for the Shichibukai of whom it was initially stated that there were 6 more just like Mihawk [
X]... It's really not that deep, it's just Oda grouping them together as the M3 - it doesn't mean they were close in strength, it simply means that there was a significant gap between these 3 and the rest of the crew (obviously excluding Oden).
This all really just stems from Roger downplay. He's underestimated because he's featless, but if someone said Scopper Gaban pushes Prime Whitebeard to extreme-diff they'd get laughed out the building and rightly so. Whitebeard and Roger were equals, even Kaido who was the strongest admitted that Roger was unmatched, and brought the world to its knees with his haki alone. And the gap between Kaido and mid top-tiers is not an insignificant one - don't forget that Kaido absolutely ragdolled ACoC G5 Luffy in 1047 whereas Kizaru was matching ACoC-less G5 Luffy.
Kaido, a high top-tier, high-diffs mid top-tiers.
This Kaido admitted inferiority to Roger and even went to MF just to fight old Whitebeard. If Roger is capable of high-diffing someone of Kaido's calibre, then even mid top-tiers are getting mid-diffed or worse.
The ceiling is high. Garp and Sengoku, two men of Kaido's level fighting together against Shiki was
still a high-diff battle lmao. So if Shiki is above Kaido, and Roger's above even Shiki matched only by Whitebeard, then the gap between Roger and mid top-tiers or worse is insane. For Gaban and Roger to even begin to be considered the same level, prime Gaban would have to be Kaido level. If old Gaban is low top-tier and looks as good as the likes of Garp and Rayleigh, then this is possible. If old Gaban is no longer a top-tier and is instead YC1/YC1+, then there is no chance that he was on Roger's level in his prime - simple. We'll find out soon enough.