Well, I believe that some help is mixed with plot/gameplay, but usually plot related.

But the norm of adding little help to the final battles just to make the game play easier isn't really justified (if it's only gameplay related).
I thought FF games weren't supposed to be that easy? Unless it's plot related then that would be fully justified.

Now, look at some other FF with the similar help:

FF7 : At the end of the battle, you automatically set to the last limit break, Omnislash. There's like 90% chance for Sephy not to kill you, because of what reason? It's because when Sephy was being weakened, Cloud automatically uses Omnislash on him, so it's plot related. There's another proof: You see Cloud using Omnislash on Sephy in the end of FF7:AC. Again, he used it because Sephy was almost dying, therefore it's plot related.

FFX : There's also the help of an angel, reviving one of your characters. For what reason? It's because YY only wanted to fight against aeons, not the characters. You won't die, so it's plot related.

Any other FF that have the smiliar help? I never played the other FF games.

Understand what I mean?
Ok, let's go back to the FF8 angel. Future Esthar, what you said is interesting.
Why? You know Ellone, Squall asked her to find Rinoa in the Space as Ellone wanted to help him. So it may be plausible that Ellone also wanted to help Squall/the party at the end of the battle, with the help by the angel. But I still stand by my theory.