One common theme is the clash of cultures. Since it's a crossover, different cultures from the FFXIV world and the other crossed - over world collide, which makes for interesting storylines.
One that stands out is 'Crossover Chaos in FFXIV'. It's a fanfic that throws in all sorts of crossovers, from different game worlds to various mythologies. It's a wild ride as the FFXIV characters have to adapt to these new and unexpected encounters. It also has some really interesting character development along the way.
One idea could be a crossover with another popular RPG like 'Dragon Age'. Imagine the characters from FF13 in the world of Thedas, dealing with the different races and magic systems there. Another idea is a crossover with a sci - fi universe like 'Mass Effect'. The technology and alien species in that universe would create a really unique setting for the FF13 characters. Or perhaps a crossover with a classic fantasy like 'The Lord of the Rings'. The FF13 characters could interact with hobbits, elves, and dwarves, which would be quite a sight.
Another interesting concept is to have the chakra system from Naruto integrated into the FF7 universe. Maybe the materia could be enhanced by chakra, or characters could learn to use jutsu instead of magic. For instance, Aerith could learn some healing jutsu to add to her abilities.
First, you need to be really familiar with the FF13 world, its characters, and its lore. Then, choose the universe you want to cross it with. Once you've done that, think about how the two worlds will interact. For example, if you're crossing with 'Star Wars', how will the Force work in relation to the magic in FF13? Start with a simple plot idea, like the FF13 characters getting lost in the new universe and having to find their way back while dealing with the new challenges there.
Naruto and Cloud would be a very interesting pairing. Naruto's positive attitude and Cloud's brooding nature would create a great dynamic. They could learn from each other's fighting styles and philosophies. Cloud could teach Naruto about the importance of self - reflection, while Naruto could show Cloud how to be more open and friendly.
The story of FFXIV 1.0 was a mixed bag. Some aspects were engaging, but it had its fair share of flaws, like inconsistent character development and a confusing overarching narrative.
The Heavensward expansion has an amazing story. It focuses on the Dragonsong War and the relationship between man and dragon. Estinien's story arc within this expansion is really engaging. He starts as a dragon - slayer with a one - track mind but as the story progresses, he grows and changes, learning about the deeper issues between the two races. And the landscapes in Heavensward add to the overall atmosphere of the story.