I personally view the arm as just a design, whatever powerlevel Oda was originally planning for Shanks is largely the same. It was also forced to him by his editors at the time.
Anyways, Shanks has the better feats and trajectory of feats until I’m proven otherwise. Embarrassing another top-tier with haki from miles away is not enough of a red flag for people? What about one shotting the guy that just defeated a fellow yonko? (Way superior feat portrayal-wise than Kaido one shotting post-WCI Luffy). What about his haki being directly compared to Joyboy’s? If that’s not enough to put the nail in the coffin that he’s Roger 2.0 then I don’t know what will be enough to convince the readers at this point. Oda was even willing to throw Rayleigh under the bus btw in his latest SBS saying that only Shanks was capable of mimicking Roger’s moves.
Yeah, it was initially an editor influenced decision.
However Oda has well integrated this into the story, with Mihawk, Whitebeard and others mentioning about it. With Shanks outright considering this as a "bet on the future ".
If this had no impact on power level, why did Mihawk stop dueling Shanks and considers this a betrayal?
This being retroactively intended as a sacrifice is also why Oda made the lost arm his main sword arm.
Certain narratives being pushed/influenced by editors doesn't mean it doesn't impact future narratives and get integrated in the series.
Another example is supernova. Look at how much Law, Bonney and even Kid has impacted the series
Shanks definitely has better feats in the story so far, this is undeniable. However that's also because Mihawk hasn't really done anything yet in the series, it isn't his time yet.
What feats did Kaido have before his time came? What feats does Dragon have? You get the point.
As for portrayal, I think Mihawk has it. They used to duel for years, before Shanks lost his arm. As far as we know, Mihawk was never treated as his inferior there. I think it's reasonable to assume they were equal during the time. Once Shanks lost his arm, did Mihawk somehow grow at a lower rate than Shanks, when he managed to keep up fine for the years they dueled each other?
This is even ignoring Mihawk being WSS, and Shanks so far has shown no other fighting style than swordsmanship
Shanks copying Roger is again intended to show his potential. He's the potential man of OP. He was the obvious mid gen successor to Roger, as shown by inherentance of straw hat.
Shanks definitely is Roger 2.0....with one arm.
