I don't think that there should be a sequel for many of the various opinions already mentioned above. I also think that the idea of making sequels to final fantasy games and then making the excuse that this happens to give the story of another is something that should never be repeated again. 'Tidus' story' was good but then adding 'Yuna's story' was verging on the border of storyline desperation.
What will it be next - 'quina's story', 'steiner's story' perhaps even '(SPOILER)ozma's story'
We should leave each final fantasy world behind and look forward to the next without clinging on to the past games forever.