Why's tartaros arc considered the best arc in the fandom? Anybody who doesn't like tartaros arc and watched fT, there's definitely something wrong. It's like saying labyrinth arc is good.
The comparison of Tartaros and the Labyrinth is absurd, they are not remotely similar. For me, Eclipse is better but fans quite like Tartaros because it has some cool stuff:
1) The last guild of the Balam Alliance comes on stage
2) Tartaros begins his arc by attacking and killing the wizarding council and ancient wizard saints
2) We saw more about Zeref and Acnologia and they introduced a new enemy that a priori was believed to be at the Acnologia level (END)
3) We saw a wide variety of enemies (designs) and powers which were great
4) Lucy takes a great role and stops being the weak girl, which is great because Lucy is the protagonist of the story and until then Wendy and Erza looked better
5) The spiritual king comes into action
6) We had quite a few emotional moments, like Lucy destroying the aquarius key, Elfman betraying the guild to save his sisters, Laxus has a great vindication moment or Natsu reuniting with Igneel
7) the last plot twist where Natsu was the same END was also great
8) Natsu abandoned his friends and the guild dissolved
The problem with this arc is that over time Mashima ruined it in other arcs or they just didn't lead to anything, for example Elfman didn't get retaliation for what he did, I expected him to be kicked out of the guild or when the guild regrouped, they won't let elfman join or something else. Lucy has a chance to find the new key and reunite with Aquarius, there was no problem with the magic council dying, they were quickly replaced, END was wasted, we never saw him enter the scene, we saw a half transformation that was minimized by Gray and Erza(something absurd when he came from easily defeating someone who controls time), practically the entire arc of alvarez destroys the arc of Tartaros