It's called good writing. I'm sorry FFVIII didn't have any of that.
Dropping the father of one of your main characters into a plot void and making him irrelevant is just flatout bad writing, especially given what prominence he had upon his introduction. (also the fact he married Julia)
Having Rinoa amend her relationship with her father would have done nothing but strengthen her character. And god knows she needs it because her character is a gasping cripple clinging to Squall's character. I merely ask for some character growth free of the intolerable Mr. Leonhart so Rinoa can actually do something on her own without the game making her look like a complete fool.