Okay my first blog post, so please be kind.
The English dub is now up to the Eclipse Celestial Spirit arc, so I am re living it now and have some thoughts on its, it is a much hated arc among fans, and really didn't have to be. It has so much prudential, in the arc like most Fairy Tail arcs to be fair, started strong or showed great prudential, had a shitty middle part, and ended strong, that is a Fairy Tail arc in a nut shell.
I liked The Key Of The Starry Sky arc, it has its own problems too, but I enjoyed that more than this arc, and one of the reasons is it felt connected to other arcs and overall story. The Eclipse Celestial Spirit arc was determined to be completely stand alone and have no connection to any other others arc past or future. A good filler arc would give you hints on what is to come, we didn't get non of that.
What would I have done to improve it.
1) Hints of Yukino's sister, golden opportunity to give us hints and teases on who Sorano really is. An arc that had Yukino and Celestial spirits play a central role here, this was just begging for a Sorano hint. I know they all meet Yukino during the GMG arc, but that was when the world was in danger, and didn't have time to make these types of connection. But I thought it would have good if in "Stake My Life in Hospitality" when Aires saw Yukino, she would be very scared of her. And later when Aires turns evil, she could say to Yukino "For some reason when I look at your face I just hate you."
Which brings me to
2) I know their memories are gone, but they still sensed that Lucy and Yukino were there owners, so they could still have subconscious memories. I would have the Zodiac Spirits subconscious think of Celestial mages of people who threat them as tools. Most Celestial mages we meet in this series are terrible. Use that, have them lump Lucy with people like Karen and Duke Everlue and Angel.
Also perhaps have Virgo bust into jail and beat up Everlue.
Plus I would have Libra and Pisces find Kagura and have a rematch with her, and state "we won't lose this time because we are no longer under control of that weakling (Yukino)". Any excuse for more Kagura is always welcome.
3) More Sabertooth, where are they? You have Fairy Tail doing everything they can to help their guild mate Lucy in this trying time, and Yukino is going through the same thing, where are they? At least Sting, Rogue, Lector, and Frosch, it seems of late (reading the spinoff manga and who got more panel time in chapter 461 and 462) the A team of Sabertooth are the dragon slayers, the girls, and the Exceeds. And the rest are just the B characters.
Them lack of helping when compared to Fairy Tail, makes them look bad. If they are not in it, at least explain their absence. Perhaps Yukino is keeping this a secret from them, maybe she is afraid if they found out, they would kick her out again, which would show that Jiemma still has an emotional effect on her, and would have the past arc have an effect here. What Jiemma did to her should still leave an emotional scar that will take time to heal.
Off topic, I wish we saw how Yukino rejoined Sabertooth, how she came to that decision, and see her home coming. Though I think her home coming would be close to the same as Minerva's home coming, and I could see them not wanting to do that twice, and Minerva's home coming was more important to her character and being shown than Yukino's was.
4) Lack of consequences, at the end of the arc, the Zodiac spirits they don't remember anything and allowed to just live their lives like it never happened. They should have at least been told of what they did and said and have to live with that guilt. What is the point?
That is what I would have done to improve this arc. They could have still have had their goofy battles, I don't hate that as much as other people do.
Tell me what you think, and what chances would you make.