After Advent Children came out, it just inflamed the entire debate all over again, because to Cleris fans, Cloud seems to abandon Tifa and his home because of guilt over Aeris's death, and because of his geostigma. Additionally, Cloud and Aeris seem to have a more functional relationship than Cloud and Tifa, because although Cloud and Tifa are seen together a lot, they don't seem to understand each other as well as Cloud and Aeris.
I think the major problem with is that there's a strong not only misinterpretation of Cloud/Tifa relationship, but Cloud/Aerith as well.
Cloud/Aerith, imo, definitely had strong degrees of bittersweetness in those scenes, but they did not have a functional romantic relationship. It's even up in the air if they interacted before that, and imo, it seems that Aerith leaving the church symbolized that he'll be okay without her.
Also, even without going on how Cloud/Tifa is dysfunctional/functional, the story presents that what Cloud is doing is harmful, and that he needs to fix it. That makes the problems withing Cloud/Tifa an aberration, and that him leaving the family something that he needed to fix, and presumably did fix (otherwise I just wasted an hour and half of my fucking life).
The theme is for the story not to let your past mess up what you have now. He let Aerith turn into a figure of guilt, he let Zack's pride/sword rust (hurr durr), and he left alone Tifa and two kids he was helping raise. Then he overcame them.
In the game, Cloud has a flashback where he visits his mother. She asks him if he has a girlfriend. He replies no. She continues, saying that he should have a girlfriend that is older than him to take care of him. Aerith is one year older than Cloud in FF7 and Tifa is younger
Honestly, red herring. I think one of the reasons why Aerith's death was such a punch in the gut is because there are all these "clues" and in the end they didn't matter.
Also, the idea of her having an older girlfriend is to take care of him. She says this explicitly. Aerith might be older, but it's Tifa that looks after him.
Thaaat said.
I can't be the only one who thinks that the Aerith death had motivated Cloud almost more than anything in Final Fantasy. And that there was definitely something special about it. I dunno, it seemed a huge crux of the game was about this.