Large ensemble cast, all distinct from each other, and you get to actually use all of them. There are not really any bench warmers.
Full open world with tons of cool shit to find.
At the time it was made, had the most robust final boss encounter on the SNES. Chrono Trigger being 2nd.
Compelling story and all (except 4) the characters have robust backstory & personal drama.
Lots of really cool abilities and equipment options that were very new to final fantasy at the time such as Tools, Blitz, and Rage. Relics like Master's Scroll and Celestriad makes it fun to equip everyone.
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It says right here in Matthew 16:4 "Jesus doth not need a giant Mecha." https://i.imgur.com/dQgC4kv.jpg