I feel like developers just need to wise up and figure out ways to make interesting software that appeals to broader audiences. And by broader, I don't necessarily mean younger. But somehow I doubt that will happen if the arm-flailing minigame collections that are spearheading Kinect's launch sell abhorrent amounts of copies. However, think about the established demographic of Xbox 360 owners (i.e. not little kids)--it seems like Microsoft and developers working on Kinect supported software will have to cater to them in some way. After all, this project has taken millions upon millions of dollars and tons of time to bring to fruition, you know? They need to make that back somehow, and I don't see that happening by effectively shifting focus away from the people who already own and are actively playing 360s.
Honestly, I think its very rare these days to find a game that's actually WORTH the $60 that we pay. Surely, we'll still pay it often enough, but....few games that I paid $60 for I felt earned that price tag (from a design standpoint, not a technological one--of course a good chunk of the development cost for games these days goes into the R&D side of it). And apologies for getting all preachy-like.
As far as this topic is concerned, I would consider getting ODST if it was not $60, because I was never really much of a halo-player. ODST seems like it brings a lot of fresh ideas to the franchise, but $60 is a WHOLE lot to invest in something that I might not end up enjoying. That might be another angle to look at it from.
The structure of final fantasy almost necessitates that it be linear, as it has a tightly scripted story progression. Of course it will most likely allow for some degree of exploration (to carry out side quests and the like), but if its like most other final fantasy games, a player will not have full access to the world until he/she is a ways into the game.