@Ryuksgelus:
But we've seen Croc be injured by far less. If he can take a Joz punch he should be able to laugh off a base Luffy or fully powered Franky punch back then and certainly now. Its like he has greater than Lucci level toughness now which is a ridiculous power-up or major contradiction if he was defeated by a kid weakened by poison with stamina like that in Alabasta. Also makes Auger comments on Ace's endurance carry less weight than it originally did for readers. Back then we though it was impressive seeing how relatively defenseless Enel&Croc became once they lost their Logia invulnerability.
After taking that punch it essentially means Luffy couldn't defeat him now even with Haki upgrade or at the least Croc would give him an even more difficult fight than before despite the power increase from our hero. So again here is hoping Don was holding Joz back before the first punch and only got him completely in control when he got on his back.
Well, in Croc's consistency's defense, he seemed relatively unphased by Luffy's hits up until the last attack. And I don't believe that Luffy can punch through bedrock even with a Jet Gatling. And Jet Gatling's strength has been somewhat inconsistent as well. I believe that Luffy has a wildcard kind of strength, but that on occasion, especially when he's on his last dregs, he pulls an attack strength from his desperation haki (lol) that is leagues above his current level of strength.
In the same way that no one could have predicted that a slightly winded and leg injured Lucci would fall from Luffy's last attack, Luffy's Storm was waaaaay stronger than anything we could expect from regular Luffy, even at this point in the story.
Hell, Luffy and Zoro's base strength skyrocketed just from having a good reason to fight. This was commented by a CP9 member, I can't recall which. But there is an extra level of "determination" that Luffy pulls from his ass that is ridiculously over his average attack strength. When he was screaming I will surpass you he was probably giving it his true all, something he can't really control yet. I don't like talking about haki, and I don't know if this was the earliest manifestation of it from Luffy, but what is certain is that, be it haki or not, he can bring out a strength that is above his level of strength. Eventually though, he should be able to do it with every attack or he will be owned.
What is not crazy to hypothesize is the fact that Luffy's end potential strength is probably higher than José's, so perhaps it isn't as ludicrous for Luffy to defeat Croc with his strongest attack when he was using his full potential. The problem with Luffy is that he didn't really become physically stronger during the entire manga from what we've seen. Gear 2nd is the only physical powerup (apart from Nightmare Luffy) that he ever got in terms of physical performance, but that is a stimulant. He was already a beast from the beggining, just in terms of strength. What he really needs to work on is putting an extra oomph into his attacks that all these top powerhouses can, and do it consistently, not just when he is about to die, and absolutely must. And also hit Logias with haki, obviously.
Basically, I think that if Luffy fought every battle from the beginning as if it was his last chance he would be many times stronger. Something needs to happen in this war that jump starts his ambition (i'm not talking about haki). I'm talking about the fact that right now he is quite different from the Luffy that we knew and love. He's taking all the help he needs, and accepting his weakness. The old Luffy would still be screaming I'll kick your ass to guys who were way over his League, like Croc was. The current Luffy is much more timid in terms of his determination to best his opponent. His defeats seem to have humbled him considerably. It may be subtle to some, but his attitude is, I feel, different. Of course many may disagree, and I could be wrong, but I think that the way that Luffy get's better is psychological at large. He needs to be saying that he'll beat his opponent no matter what, not saying that he'll fight even if he dies. It may not look like much, but in one affirmation there is the determination to get better until he wins, and in the other there is resignation. To me, the difference translates to:
1- I'll be better than you.
2-I'll try my best.
With that first mindset he defeated a guy who can take brilliant punk and land on his feet.
With that second one he's getting owned and needing help all the time during this war. I think that when he really takes matters into his own hands and can trust his power again, he will truly unleash his full potential. And that is when, I believe, he will unleash his haki. (sorry for the end)