I find it absolutely hilarious that people are whining about this and don't understand what he means. Square already said that single number titled games will not have characters from other universes visit FF games. This explains why Cloud and Squall were never in XIII-2 or LR. They stated that it would confuse the fans and would in turn make no sense. They only said creatures like Gilgamesh, Omega Weapon, Ultros, etc. They could make a reference to her like how Zidane referenced Cloud and Sephiroth in FF9 or they might do skins of her costume to female characters, but they won't plop her into other games.
He's talking about such games as Tactics, Dissidia, Theaterythem, Kingdom Hearts, MMO guest appearances etc. Where it appropriate to see said character.