I gotta say, I think FFIV get's too much love these days. Certainly, for its time, it elevated RPGs to a new level. But I would never want anyone to create a new game like that. Since then, other games have elevated the genre a dozen times above FFIV, namely FFVI. The RPGs prior to FFIV are really basic and childish... FFIV tweaked and grew things just a little bit, to be the best RPG of its day. But by today's standards, I think FFIV just doesn't cut it. Maybe the fact that it had a plot and characters was good enough for its day, but the plot and characters that are there are pretty terrible. All the characters are absolute stock archetypes: the hero knight, the damsel in distress, the friend/nemesis, the bratty token children. I have nothing against archetypes, but when they're portrayed as generic and 2-dimensional as FFIV has them, it's just no good.
The plot is also pretty terrible: Moon Men trying to take over earth by posing as it's strongest leader. I mean, that's it, there it is. Every character who dies gets resurrected, even if their death is honorable and self-sacrificing.
Look, the core plot of most RPGs, even modern RPGs, is pretty basic and often laughable, but usually what makes it is it's nuances and delivery. FFIV had no nuance. It took cliche after cliche, and fed them to you straight.
Don't get me wrong, when I first turned on FFIV back in 1992, I was blown away. But games were crap back then, just coming out of the dark ages, so it was easy to be amazed. But I find FFIV to be pretty unplayable today.