Why not? I mean, sure, there are people who hate those damn Cheevos, but I can see 'em providing a good deal of incentive for people who want changes to the game.
To bring up WoW(Always reviled and spat-upon), achievements are generally there for one of 3 reasons:
1. To show what your character has done
2. To entice people to experience content they would not otherwise be interested in
3. To provide additional challenge beyond what is normally necessary for game progress.
Since a lot of people are complaining about FFXI being easy mode now, number 3 could be a good idea. And since there's not many people outside of Abyssea these days, number 2 could also be put to good use.
Course, people will probably cite PS2 limitations and all. Or the structure of the game or whatever the excuse is. I'm just sayin', could be a step in the right direction.
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