FFVI was basically glitchy as all hell and the dungeon designs weren't very good. Also the ratio of Good Characters to Total Characters was low and at least one would literally destroy your save if you used her. Also you tend to happen upon really simple things you can keep spamming that basically win every battle.
I love the style and atmosphere and storytelling, I just find it miserable to actually /play/ it.
And, to me at least, that idea is 1000 times more terrifying than Sephiroth wanting to destroy the planet because his mommy doesn't love him/really exist.
Prior to Square's endless retconning, the thing with Sephiroth is that he's a byproduct of Shinra's sketchy energy business. It's not so much that Sephiroth wants to destroy the world so much as it is the planet wants to kill humanity/commit suicide and Sephiroth's just the thing through which this is being did.
I mean I'm pretty sure in the original FFVII Sephiroth's this insane radioactive zombie and then people got really turned on by this for some reason so Square was like FUCK IT WE NEED MORE ATTRACTIVE RADIOACTIVE ZOMBIES.