I personally felt Hiro rushed for the last 30 chapters or so whatever may be the reason.The way END plot was done(it appeared suddenly and disappeared suddenly),Zeref being defeated in an anticlimactic way,Acnologia's final battle everything hints at rushing.
That's true, but the same is probably the magazine that told him to finish as soon as possible.
The reason is that the manga is 11 years old, it's a strange date to finish a manga.
Usually it's 5, 10, 12, 15, 20 when a manga is over, I do not remember having seen 11 years.
Even if mashima had said we were coming to the end, he also said that there was still a lot to do and say about FT.
And with all that was left develloped we had enough to do at least another 1 year, to be 12 years old.
Besides, we still expect these "" many "" project on FT, we had the amine, the novel, its only 2, it is not enough to use the therm "" many "".
Well, look at OP it's been 20 years, it will probably end in 5-10 years.
Bleach is 15 years old as a naruto to only mention them.
Silent voice is 5 years I think, magi is 12 years old I think.
In short most of the time it does that.
Don that's why 11 YEARS is weird.