Well it's too bad that you don't want to continue your fiction, because I found it interesting and funny ! The most funniest part was when Natsu and the others was worried and cried "OLD MAN!" and Zoro, in other hand was like "Yo!" with the peace sign after being "beaten up"... As if hahaha
Well hope one day you will find inspiration and continue this story

I forgot one thing to write.
You could make Jose realize who zoro is and letting Zoro and the rest of team natsu out of there base without a fight. That would show how badass zoro is and make Erza begging him to train her.

I have a few ideas what you could do.
First you should make zoro older like 140 (you can explain that Law used his fruit to slower zoros aging proces and thats the reasen he looks like 70) so that the guild reaction,, He is still alive "would make more 50 years is in my opinion not enough time for such a drastic change like magic in the world.
You can also make haki the source of magic or that magic is a different type of haki.
It would explain why people can use magic in this era.
You can also make haki The One Magic which is the originall source of all types of magic. You can also make that magic can harm every devil fruit users because its a form of haki and because everyone can use it less people would eat it a devil fruit. It would be less op and could lead to a world with out devil fruits.
And now about Zoro teaching Erza.
Dont make Erza using(learning) Santaryou, because i think Erza will be not able to master reason is if you would have a blade in mouth and you tried to fight with it you would probably damage or break you jaw. Zoro trained himself in that when he was a kid and thats the reason why he is able to wield a sword in his mouth and fight without insted of 3 sword let erza learn fight with 4 swords. We have seen her using it ( usind her feet to wield 2 extra swords)and this would give erza a new special original style insted coping every thing from Zoro.
And because you want to rewrite the story here are a few proposal
You could do that before Zoro fights the 3 masters they feel a demonic aura coming to them but seeing zoro a old man made them laugh forgeting about what they feelt 5 seconds ego.
And you shouldnt make zoro faint after that fight. Even if he is like 70 such,, weak" attacks shouldnt be enough.
I mean we have seen a sick Whitebeard taking a lot of damage and he died standing so seeing zoro faint from a few attacks is just dumb.
Thats all. I hope i could help you somehow.

I like it.

Wooo Awesome! *thinking* if Luffy's going to kill ach-achronologea then... actually I haven't really thought about it?... but... I want Luffy! ... maybe the rest of the ASL?!

There are some misspellings but overall a very good story so far.
Please continue.

Woohoo awesome story!... hmm it was 50 years right do Zoro should be... 71!?

I GOT THE SECOND REVIEW! Sry first time this has happened in a while. Love the story so far. Just a suggestion but if you make Natsu or Lucy oblivious to the Great Pirate Era you could have Ezra or someone else explain the significance of it in order to flesh this world you've made. I hope that this at least gives you some ideas. Can't wait till the next update!

nice!