Now, on to the meat and potatoes: This is a lot of fun. Random encounters are back, but they are easily escapable if you aren't interested in fighting. The preemptive attack is done much more cleanly, giving you the opportunity to attack before battle mode is activated.
Speaking of the battle system-- say what you want about FFXIII, there are plenty of bad things to say about it, but it's the best battle system so far. The sequel improves upon it significantly. The ability to use monsters you've fought as allies in battle provides for more varied paradigms, and shifting between these paradigms doesn't annoyingly pause combat as it did in FFXIII. The only downside is that they've included a new mechanic in battles called "Cinematic Action." Yes, my friends, quick-time events (or as Yahtzee Croshaw of Zero Punctuation fame calls them, "press X not to die") are in a Final Fantasy game.
Outside battle, from what little I can tell from the demo, Square Enix has addressed many of fans' concerns-- everything seems more open, there are NPC-given sidequests, there are towns with shops and people to talk to. The trailer that played after I completed the demo showed many little diversions to pass the time, like casino games and chocobo racing.
I'm looking forward to actually getting my hands on the full game. Skyrim isn't done with me yet, and I want to finish up some things in LittleBigPlanet 2, but then I think I'm going to be all over this.