If I could comment on a few points?
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I loved the Sphere Grid!
I don't know why, seeing as the first time I played
FFX I went around it backwards for half a game, and then started again, but I did like it.
And as for battle systems - I'm interested to see what
FFXIII will bring. Apparently it's going to be somewhat like
FFXII, where you can see monsters, but it's also going to be in real time. And from what the videos of FFXIII show, you might be able to move around within the battle.
And in
FF Versus XIII? Now that's a system I'm excited in seeing. Since Nomura is involved, we've got a nice system somewhat like a cross between the
Kingdom Hearts and
FFVII: Dirge of Cerberus systems, which can take place inside and outside, and can move between the two,
SEAMLESSLY. In fact, the whole world is rumoured to be seamless - as in no loading screens.