I don't get how in the hell you could relate to FF7's characters any more than Xenogears', when they're in an equally outlandish situation, unless of course you live in a world controlled by an evil corporation siphoning life out of the planet and spend your days chasing after a man in black.

Your suggestion of relating more to the characters? Entirely moot.

And realism? I hardly think discussion of a game set in a world entirely different for our own warrants the suggestions of REALISTIC characters.

Oh and the fact that all the characters in Xenogears have been linked continually through every cycle of reincarnation? Yeah, I'd say that was a good reason they're all together, compared to "OMGZ SHINRA IS EVIL, LETS BEET 'EM ;(".