FFXIII had its good points, just more bad points. It was too linear and the plot was pretty terrible. But the setting was good (not to mention stunning to look at) and the mythology was quite interesting. FFXIII-2 focused far too much on 'fixing' FFXIII and not on being its own game, although it was overall an improvement.
I personally really like Lightning and I think Ali Hillis is a fantastic voice actress, so I'm very pleased to see a game focused on her character.
What excited me most about Lightning Returns' initial announcement was the apparent attempt to create an 'action-oriented' Final Fantasy, essentially an Assassin's Creed style FF game. Final Fantasy certainly needs to move away from the turn-based text menus that have been a staple of the series, as gaming has moved on significantly from this. However, as more footage has been released, I'm worried this game won't go far enough. It looks as though Squenix are struggling to let go of out-dated mechanics and take a risk with something new.
I'll admit, its why I'm one of about three people who actually liked FFX-2, as SE used the first ever FF sequel to try something different. It might have had its issues, but at least they tried something new.