I didn’t really care about the terrible attempts to continue shipping characters, like Gajeel/Levy or Gray/Juvia. Not sure what to think about the disbandment of Fairy Tail. But the whole Doranbolt thing just feels like one plot twist too far for the Mest/Doranbolt side-story. At least the re-use of Oración Seis characters is okay in my book, even if the battle between Jellal and them seemed completely superfluous.
And E.N.D. is Etherious Natsu Dragneel?
So either there’s an Etherious version of Natsu, or Natsu will turn (back) into E.N.D. as he grows stronger. I’m betting on the latter; why else will Zeref want Natsu to be the one to kill him? Moreover, E.N.D. was created by Zeref to commit suicide, which sort of fits in.
But while that’s a decent plot twist, why reveal it NOW? It ruins any suspense you might have tried to build up as we head into the final arc of the series.