I fail to see how this isn't a matter of reputation. The fact that people like Rogers, Shanks (+ crew) and even Big Mom were even in this to me seems wrong. How can we compare what we can't see? Reputation and force alone don't necessarily account for wins - Luffy was definitely weaker than Enel in the Skypeia arc, and even in this tournament Killer had a much better reputation than Buggy, however the fact of one piece is that the stronger pirate doesn't always win. Now, I'm not saying Roger would lose this fight - he WAS the pirate king, after all - but voting Roger/Shanks mindlessly seems pointless. I enjoy debating strengths and weaknesses, being able to analyse how two abilities would match up, and Rogers/Shanks are basically an automatic win button. It just ruins the whole point of this tournament. Ask anyone who watches/reads One Piece who they think the strongest pirate ever was, and odds are they'll say either Whitebeard, Shanks or Rogers. We already know that - why have a tournament to show what we already know?
Now, back to the fight - I think Luffy was fortunate against Shiki - during the first encounter he effortlessly defeated Luffy, Zoro, Usopp, Sanji and Chopper, at the same time. Following that, he beat Luffy again, using water this time. Now, were it not for Billy the baby Zapdos electric bird, the trick by Usopp and Nami to draw Shiki into a storm cloud, AND the fact Shiki, upon seeing Luffy place his foot into a storm cloud was anticipating Luffy being electrocuted as opposed to using it to power a kick, Luffy would have lost again. The mere fact that Zoro survived Enel's attack shows us that Enel wasn't being 100% serious, as he definitely expected to be able to kill Luffy with electricity, and may I point out that the kick that beat Shiki was a lightning-imbued axe with enough power to destroy an entire floating island! Remember that lightning Enel used to strike down Zoro? When he grasped the swords and ran a current through them? Yeah, that didn't even leave a scratch on the floating island they were on. Saying 'Shiki must be weak because he was beaten by Luffy's kick when Enel didn't kill Zoro' is like saying 'Shanks must be weak because he lost his arm to a sea-king and even pre-SH Franky managed to beat one of those!' While the incidents mentioned are technically true, there was a lot more going on than the gross over-simplification that you've used. Shiki is - at the very least - similar to Crocodile in terms of strength - both beat Luffy twice, easily, before underestimating the SHs and losing. Now, the only reason I think Mihawk is stronger than Shiki is that Shiki's main weapons - swords and very very large things - are both the areas where Mihawk excels. Just the Don Kreig arc alone showed that - an entire battle fleet was taken out in one swing, and Zoro - who even then was a famous swordsman - was taken out with immense ease by Mihawk, who wasn't even trying AND using a dagger he normally uses for cutting up his food. Both are incredibly strong - in my opinion stronger than most characters we've seen in one piece short of the Yonkou, Rayleigh, and possibly some of the admirals - and as strong as Vista is the mere fact alone that Mihawk has the title of 'strongest swordsman' shows who'd be the victor in their battle... As for Pekoms, he's strong, has Haki, and good defences. He is one of the top of a Yonkou's crew, but at this level of the tournament that doesn't mean a great deal...
