Maybe I'm just complacent about the other characters because I didn't have to trudge through as much dialogue for them. Yeah, Tifa's bosom is more developed than her personality, I didn't like her either. Yuffie's enthusiastic though. I wonder if Square's just unable to make good central heroes. They're either silent protagonists (Crono, Mario) or we wish they'd be silent more often (Cloud). FF6 seems to fare better, but it doesn't really have a main character.

And it's OK, don't worry about drifting where the conversation takes you. Fire Emblem has a reminiscent system where your stats rise if a character fights nearby somebody with whom he or she has a relationship, and it works nicely. What helps that game (at least the first US Fire Emblem) is that the characters are interesting and the dialogue is well-written. So we actually want to see the characters' romances and friendships, and the results are humorous and often very sweet.