Meh, I think any FF is open when it's finished. The characters can easily be picked back up for more adventures (except the dead ones lmao).
But yes, it looks like I was talking crap after all. I was thinking of the 13-2 ending . I'll blame it on being ill! I don't get the chance to use this excuse very often!
Lol! Nice excuse yeah XIII-2's ending was clearly set up to lead onto XIII-3.