I get that, but I see it differently. I don't think he has great power and little durability. I think he has a lot of both. But it's cool. We'll see for sure when he does fight if he can take as much as he dishes out. As long as it's not another boring fight done with one shot.
I guess BoS Natsu could kill August if he landed a blow 
That isn't the reason they were at full power in Tartarus, Sting and Rogue achieved full power in Tartaros once Weisslogia and Skiadrum got out from inside them, the Dragons were actively inhibiting their growth as Dragon Slayers, why do you think Natsu had to take in external elements to enter Dragon Force each time? Same as Wendy in Tartarus. Compare it to Sting and Rogue who activated their Dragon Force internally, it's clear they were never at peak power till Tartaros..
Bradman is likely better than Mard Geer with his thorns, but don't forget Gajeel went in recklessly, desperate to finish Bradman for the sake of Levy. He left himself wide open because of his urgency to save Levy. For one who says he could pick me apart you have holes in your arguments. Not impressed at all.
Lol if anyone loves to charge in recklessly without thinking its Natsu, and yet he was able to dodge multiple thorns with ease while Gajeel got hit with the very first one.
I don't understand why is this illogical
Natsu had nothing holding him back or causing him to do things recklessly. Right after Levy's mask came off and he found out that skin can absorb the particles too, Gajeel was desperate and reckless. He went running at Bradman only thinking of a way to hit him to beat his ass. Do you read the story or just see the simple things only?
No they are not.Also @Dr. Monty your point about Juvia being able to survive Serena's attacks is a little moot, look at the scale of the attack he used on Natsu and co.
It's obvious which is the most dangerous attack due to the sheer scale, you literally have the ground tearing apart from a freaking WATER based attack when he was fighting the GOI.
Serena's attacks are definitely among the top tier among the Spriggan 12
And when does Natsu ever go into a battle with any thought other than to just "beat his ass"? You think only Gajeel was emotionally affected? Natsu just found out that his father who he had been searching for for most of his life was actually within him the whole time, and he was told that he wouldn't get any answers at all about anything unless he beat the shit out of Mard Geer. So not only is Natsu already the kind of person who always charges in recklessly without thinking, but now he has this ultimatum from his father that motivates him to take down Mard Geer or else none of his questions will be answered. So no, Gajeel being fueled by emotions and being reckless is not an excuse here.
When your girlfriend is dying because of the enemy and time is short that's how it goes. Did you read the manga thoroughly? Do you understand the difference in situation. A dragon dad tells Natsu to beat the crap out of Mard Geer to get the book. At that time Igneel was in the early stages of fighting Acnologia, where an outcome can't be seen yet. You got very little info and you are just arguing for the sake of arguing.
It doesn't matter that the situations are different, the only thing that matters is that in the end both Gajeel and Natsu charged in recklessly without thinking. You can make up all the excuses you want but the end result is the same in both cases. You make it seem like Gajeel completely lost his mind and just started swinging around blindly. Being emotionally affected should not impair Gajeel's fighting ability to the point of being unable to dodge something he is normally capable of dodging.
No they did not charge in the same way. That's why we are talking about the situation. You only see the surface of it.
Stop, just stop. We have no details about the Acno incident but just likely Acno swatted Gildarts like a fly and left him for dead. As for one shotting a Spriggan Laxus basically done that. The first move Wahl wasn't immune to he got dropped, they both basically one shot a Spriggan. Let's see Gildarts beat Serena if he was immune to heavenly body magic, the last time we saw Gildarts without his magic Bluenote was stomping on his head.
It's still a feat that Gildarts has under his belt; we don't need much details about said incident to theorize on how he got out alive, because that's simply irrelevant. The fact that he did is an enormous feat in itself.
IMO if you allow me:
Alright, after thinking about it, I finally got what you were trying to say with the whole Acnologia not being completely dwarfed bit. So basically, because Acnologia's still visible when compared to the explosion that covered the island, and because he doesn't dwarf humans in terms of size, that means that Natsu's FDK roar and the explosion are around the same size (from what was shown), right? Because if that's the case, then I can see how the FDK roar could destroy the island.
You guys overrate Tenrous size. Its a very small island. Acnologia is not completely dwarfed (to the point of barely being seen) by his own expanded roar, which is naturally larger then the island itself. Natsus Tenrou LFD roar being 3/4 the length of Tenrou is really not that impressive compared to the crater that the FDK roar left. I'd argue that what is seen of the length alone is enough to cover Tenrou island, we don't even need to know when it actually ends. As for width its really not even a contest, the LFD roar is about as wide as a few trees. The FDK roar is easily multiple times wider, and when I say multiple I mean in the double digits. Overall the FDK roars area is much much much greater.