I'll be completely honest, because I've seen hate and overly-showered praise on both sides. You'll get the most enjoyment out of Final Fantasy XIII if you think of it as a puzzle game as opposed to a role-playing game.
Yes, the game does open up near the end, and when it does, it's insanely good. You get a beautiful environment, lots of little sidequests and optional things to do, and plenty of opportunity to explore. You get those moments of "Whoa, what's over there?" and you can go over there to take a look. The enemies aren't sorted by power, but more like a natural environment, so until you're powerful enough to stomp everything into the ground, you're going to have to actually work your way up the food chain, so to speak.
Unfortunately, when I say "near the end", I mean the second-to-last chapter in the entire game. Let me put it this way. I haven't finished the game just yet, although I easily could if I wanted to. I decided instead to beat the chapter boss to get the last Crystarium expansion before the final boss (you get a post-game expansion as well), and instead of heading to the final chapter where we return to the linear level design, I turned right back around and went back the way I came to go back to the open area. I pretty much live there now whenever I turn the game on. Screw Cocoon and the Fal'Cie, I'm staying put. I'll get around to finishing the story, when I get around to opening all of the stat upgrades and topping off my current weapons.
I remember reading that when they started making Final Fantasy XIII, they looked at what the most popular genre of game was at the time to focus their level design around. Unfortunately, at the time, the most popular games were linear first-person shooters. Don't get me wrong, I absolutely love Final Fantasy X (although I never could get around to finishing X-2. Too much repeat of the first game, and not enough original areas, I suppose), but I would guess that it's because you get world-building through talking to people and everything instead of the occasional cutscene where they watch the news on a nearby screen, and reading the in-menu Wikipedia for details.
Anyways, I've started playing Persona 3 again. I never got very far the first time, so I started over with the Portable version. A lot of the game mechanics have been fixed or improved, but you do miss out on a few things. So, to compensate, I've also been watching a Let's Play (SuperJeenius) of the FES version of the game. I only watch up to the point where I'm currently at in Tartarus/Full Moon Shadows, but his run is a 100% Social Link run, while I'm just playing normally. So far, I'm at the second block of Tartarus, with a week or so until the second Full Moon event.
Quick question for anyone who's played this game before. I ended up making a Lilim early in the game with all four base elemental spells and Dia. It got me a huge way through the game with very little difficulty. However, I'm getting to the point where I'm going to need something stronger. I'd like to make another Persona with no real weaknesses and elemental coverage/healing. Can I use the Skill Cards on anything, or is it like Pokemon where only certain ones can learn certain moves? Any recommendations in the LV 15-18 range?