I had a brief go at Eurogamer Expo and I'm not too impressed with what I played. Battle system is near identical but with added quick-time events in certain parts of the battle. Of course, they decided not to have headphones at the booths so I couldn't hear a thing which detracts from the experience and I didn't get to try anything particularly new so I'm still reserving judgement, but I'm certainly not getting it day1.
As for the length issue, it should be fine. If they're varying the gameplay with extra side quests and mini games, completionists can probably drag a few extra hours out of the game anyway.








