As I said, Powercaling is thrown into a corner after Loki reveal.
One of the two things can happen,
- Either shanks tricked Loki into submission and captured him. And Loki is as strong as we all consider him to be.
Or
- roger vs Whitebeard case alltogether again, Roger only has Haki to his side, whereas Whitebeard along with Haki on equal terms with Roger has Gura Gura no mi, practically the strongest Paramacia type. Maths doesn't add up between them. I personally do believe whitebeard was stronger but it was an extreme none the less.
Roger haki ~ Whitebeard Haki
But
ROGER haki ~ Whitebeard Fruit + Haki
Doesn't make sense as if fruit doesn't exist in the equation.
Roger most likely had the strongest Haki of his time, that's kaidou said Haki transcends all, Looking at broken gear 5. Roger came to top with just haki.
And guess who is randomly throwing his coc on admiral faces in one piece? SHANKS!
loki Haki though, I don't see it anywhere close to Shanks.