The part you mentioned, and Windrider expanded on, was the exact part I was thinking of--that Cloud had started fights after Tifa's accident because he was angry and blamed himself.

Is there a particular reason you wanted to introduce a softer reason? I think one of the things that adds to Cloud as a character is that he is not always soft. Obviously, Cloud blaming himself is something he's struggled with from childhood through adulthood. As a child, it wasn't like the other kids didn't pick on him, but he was still...well, normal. I mean, he was normal in the sense of a kid who acts up for a reason that other people might not understand unless they do some deep digging. He was quite a different kind of child than Denzel or Marlene, but I'm sure it helped teach him some life lessons. You know, "Don't make my mistakes" sort of lessons. Or maybe given him eyes to see that if a child seems to be a bully or is angry all the time or...whatever...that he/she could very well have a deeper reason behind it.