Thats exactly it AYK. And in all honesty, chapters 11-13 (where the game opens up) are far bigger then you could imagine for the end fragment of the game. If you were inclined to get 100% completion in the game, it would take around 140 hours, whereas chapter 1-11 takes about 20 hours in total. Look at it this way, if you were to run across the entire open area in chapter 11 from beginning to end (excluding plot points), it would probably take you an hour lol.
The level/battle system and story is more then enough to mask the linearity for the better part of the first 11 chapter anyway.
Its the same level of linearity that 10 had, except it opens up way more at the end.
The graphics are completely phenominal, and will blow your mind entirely. I read somewhere that it took them 4 days to polish a single rock that appears in one scene for 3 seconds ;D, imagine that for the entire games graphics. The camera, however, is a little funky, and won't let you look at stuff you want to look at sometimes, but its nowhere near game breaking at all. I got used to it after a chapter or two.
The only other downside aside from linearity, in my opinion, is the lack of a memorable villian. The villian, in essence, was more the struggles that the main cast goes through along the progression of the game. Thats fine though, it worked out perfectly.
There is also the mention of lack of NPCs and towns. Both exist in the game, just not in the traditional sense. NPCs talk to you verbally as you run by, you just can't run up to them and interact with them with text bubbles, which is a step up in my eyes. There is also enough communication and story between the main cast, that these side NPCs become unnecessary for the games progression, and would only slow down the speed of the game. The same goes for towns. You can go in towns, you just can't stop and shop and such, you do that from save points. This is to keep the mostly frantic pace that the game promotes. It coincides with the story well. It would ruin the pace of the game and undermine the events that are going on to push you in this frantic pace if you could stop and interact with people and explore towns. Thats the way I see it atleast.
As far as ranking to others in the series... Heres my order.. (and don't flame me for not being an avid 7 worshipper, I only played it recently, when the graphics were so archeaic that the game lost the special pizzazz that it used to supposedly have

)
9
13
10
6
7
8
12
10-2
And after this we still have FF13 Versus coming out, which is supposed to be a FF story, with a kingdom hearts style battle system

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They are also talking about doing a FF13-2 now, and think they can pull off a better one then FFX-2

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