No, not exactly.
If discussing dungeons specifically, I would say that they are no more linear than most other JRPGs. That's the main point.
It's the other stuff that is different. Some games do it very well (Mass Effect series) while many others fail. Tales of Vesperia, for instance, has a bunch of towns...but they are all only like two screens and offer very little story content for the player. Just a bunch of NPCs standing in place with nothing of importance to say.
XIII lacks towns, that's the main issue. The rest of the game is par for the genre, however.
No, not really. The problem isn't just towns, although that's a big thing too.
A big part of playing an rpg is falling in love with its world, exploring every nook and cranny, and really getting invested in its world. Towns are the easiest way to pull this off and have been for sometime. That's one of FF13's core issues, it's hard to really care about the situation the heroes are thrown into and lack of world development is a giant part of this.
Second, most dungeons in rpgs these days are indeed linear, but that's just the whole point: the whole game is just one long dungeon. Games like SMT games are one big dungeon in that you can be attacked even in the middle of town, but they still employ a level of freedom that gets the player off.
Third, aside from towns, exploration is the biggest nick against FF13. As I said in the first point, exploration a huge part of playing any rpg. This not the case with FF13. Even in FF10, exploration plays a gigantic part of the game; you're teased constantly - can't beat the fish boss at the beginning? don't worry, you can beat him later on in the game; see a bunch of chests you can't fucking reach, don't worry, that stuff contains awesome loot that you can get later in the game - even while being linear, FF10 still contains many trademark rpg conventions that people come to love: exploration, loot, and customization.
By putting the game as one linear path which disallows backtracking and scoffs at the very idea of exploration, the game is doing a disservice to its rpg roots.
Other rpgs are linear, that's true, but there is a difference between a linear game that employs an illusion of freedom and an rpg on rails. No one really WANTS an rpg on rails. The only rpg I can think of that has remotely pulled that off is Breath of Fire V: Dragon Quarter. So if you're going to compare an rpg to FF13, compare it to Dragon Quarter, but whereas BOF5 is 15-20 hours long, and the linearity is based entirely around one single gameplay gimmick (that being the dragon powers and dragon counter % at the top of the screen), FF13 is a 40 hour long game who's main justification for such game "design" is for more cutscenes!
Anyways, I'm done arguing over this and I hope that the people who keep throwing around "bubububut linearity! all ff games are linear!" shut the fuck up tonight or tomorrow when they finally pop the game into their console of choice.
It's a fun ass game (really fun!) but there's very little excuse for the direction they took and the people suggesting it's not so bad without having played a lick of it really need to just sssssshhhhhhhhh and wait until they play the game themselves.