I will not change, what the Alvarez arc had, I will just add some additions, that could make the arc more reasonable:

- Showing how they stopped Marin from killing Brandish. (Like Cana using a wine bottle to knock Marin out.)

- God Serena, August and Jacob showing their powers off by stomping Bosco's forces. God Serena would use "Gale Dragon's Large Tornadoes" or something (and show off the other four DS magics) and also a little more of his personality. Then he stomps the other Gods of Ishgar by showing off his remaining three powers and is stopped by his comrades. He then proceeds to go to the Fairy Tail guild hall, but is confronted and killed by Acnologia.

- Mirajane bringing the "Juliet" and "Heine" swords to the council to never be used as enchantment weapons again or gives them to Erza's sword sets "from other dimensions" (might be cool, if Erza's magic allows that).

- Marin appearing again with the other Spriggan 12s. He will assist Ajeel or Jacob until the opponent takes him out before the Spriggan he helps.

- Ajeel's and Jacob's second battles should be expanded.

- Adding, that August suffers from a heart disease, that causes him to spill out blood (what with August's advanced age and also the blood from the mouth after Gildarts' attack, but otherwise mostly uninjured) and, that he has not long to live, he decides to end his live to take others with him, but stops his spell when he sees Mavis.

- Natsu uses his strongest attack to defeat Zeref, which like in the manga also burns Natsu's arm.

- The surviving Spriggan 12 members and underlings being taken as war prisoners and later sent to the magic council.