An attack that was weaker than the one Cobra tanked. The barrier has blocked no significant attack since. Not only that but she can just have blue stream appear behind him since she can produce attacks from all around. Plus her physical strength > Blumenblatt which fodders that barrier. Lucy has better dura feats than that barrier does if we take tanking a fodder shot from a God tier as an exceptional feat.
Jellal doesn't have the feats that says he can replicate the level of damage meteor blade caused. Meteor blade itself isn't just using Jellal's magic type either, it is also factoring both Erza's physical strength and her mp as well. Jellal's physical nor magical ability have yet to be proven to be on Erza's level. He struggled with God Serena alone. Erza beat two people who God Serena himself stated he doesn't even come close to with less effort.
Half the stuff Mashima has done in the series makes no sense. Somehow Natsu imbued with the power of legit fodder (in regards to God tiers) is able to amp him to God tier levels. Natsu's lfd struggled with Gajeel's isd and underperformed against Duke in R1 yet Natsu with lightning alone shown better feats than it by besting Duke. GS is too arrogant to simply believe someone is stronger than him without proof of such. Clearly they took him down a peg by outright beating him. Enny herself isn't even reliant on her hax.
The attack Cobra tanked did internal damage to his organs. Cobra isnt fodder either. He was a match for Erza in the Key of a Starry Night arc. I dont think Blue Stream kills Lucy either. Misaki cant shoot blue stream from behind her opponents. She can warp the space of blue dimension to inflict damage. That's a completely different attack from blue stream, and it's also entirely tanakable.
Erza struggled with Ajeel. It's not as if Erza and Jellal havent fought in the 100YQ. It was mostly a gag fight, yes...But Jellal dodged a bunch of Erza's attacks and matched her swords.
Natsu used their magic for DF, and DF Natsu is god dragon tier. Natsu never used LFD against Duke. Both Athena models are supposedly stronger than Duke and the Signario Sisters to begin with. LFD was apparently enough to destroy Athena II, prior to absorbing Natsu's fire. To me, it's pretty clear that Duke and Signario Sisters are well below LFD. Which would make them weaker than God Serena, because of the beating he gave to ISD Gajeel.
There's no evidence that God Serena has actually fought the Signario Sisters. Again, he could have simply been impressed what they could do with alchemy (bring him back from near death, world alchemy, ect). Even if they had fought, Luso could have turned him into a doll and they left it at that. There's no reason to believe the battle involved him and Ennie trading blows. Yes, Ennie can use requip, sure. But she lost to Erza without any of her enchanted weapons. The best she could do was break Erza's black wing armour. Ennie is well below base Laxus.
Well to be fair I don’t think Mages with different kinds of magics have different kinds of magic power inside them, so him believing he took Natsu’s power makes sense. He just didn’t expect for Natsu to still have some of Laxus’s left over magic power from Tenrou.
Different magic probably does have different kinds of magic power. We saw Gray get around Hakune's freezing his MP by switching between using ice-make and devil slaying. A portion of Natsu's MP is probably reserved for lightning, and that went untouched when Duke took his fire magic. There's been too many times that Natsu has been wiped of MP since Tenrou to believe he still had some of Laxus' left. LFD roar was exhaustive. LFD roar against Max was exhaustive. Eclipse stole his magic. He ran out after fighting Mard Geer. Ect.