So you wouldn't think that they won't get gil or items back because it could potentially inconvenience you economy wise?
Honestly, I'd be a little surprised if SE returned all equipment and gil.
Not only because it would have an impact on the economy of the entire game but because I doubt SE has a way to legitimately track who had what gear and how much gil at the time of the theft.
Hell, people could say they had all sorts of rare/ex gear but that the hacker must have dropped all of the useless gear or NPC'd it when dealing with the rest of the gear.
I had a Ridill and an Armada Hauberk. No, really, the guy must have just NPC'd it or something.
And then when it comes to the economy, all of that old gil and the old gear is still out there. SE would effectively be duping items while the gilsellers sell off the gear and launder the gil. Theoretically, so much gil could come into the economy that it would undo a lot of SE's efforts of balancing the economy. And then you have all of the characters who were hacked coming back, buying things, selling thingsssss, etc., etc..
SE has a LOT to think about in doing this. I do however hope that everything gets resolved well for everyone in the end.