I was deterred from discussing this in the "man in the trailer" thread, so I thought I'd discuss it here.
In October 2010, FFXIII director Motomu Toriyama was asked about a sequel to Final Fantasy XIII. Toriyama responded by saying, "I'd like to at some point make a story where Lightning ends up happy."
Now, it's way too soon to say if the guy in the trailer is Lightning's love interest, but I think that Toriyama's comment points to the fact that Lightning will have a love interest.
In FFXIII, Lightning basically had one goal: to save her sister. She accomplished this, and we saw her smile at the end of the game. So what's left that would make Claire Farron happy? What is universally accepted as the one thing that makes a person happy? Love. Great, we're going to see Lightning fall in love.
This storyline doesn't really appeal to me. I like Lightning as a loner who would think of love as nonsense. I much rather seeing Lightning as a strong leader with practical sensibilities and a somewhat cynical outlook on life. That is what made her such an interesting character in XIII, and that character would be tossed aside for her to become just another normal person who is prone to infatuation.
*Ahem* Btw, its possible that with her character they can make a far deeper love story. You know, since she's not the type to ever fall for some lame brain show off & she obviously likes to stay in command. "In command" at all times, I think we all know Lightning is the definition of independent woman....
I don't really want her character falling in love either. One thing I noticed about her is she never focuses on her own happiness but rather the happiness of others. She always puts herself last. I think there can be plenty of ways for her to end up happy that don't involve a romance. Quite frankly, given her character, I don't want to see one anyway.