Its customization was deep because you had the ability to choose a party from a cast of characters with set roles, who could be customized with espers to gain stat bonuses,learn magic spells, and use summons, and you could use relics to alter the characters abilities or give them new abilities (think of FFV's sub-job system) not to mention when you get to equipment that alters stats, causes special effects, and gives you defensive abilities. There is really nothing on the SNES that can really give the player this much customization options, hell VI gives more customization options than a lot of the FF games.

As for replay, the second half of the game is fairly non-linear from a JRPG standard meaning the player can tackle the scenarios in different order and not even bother getting back some of the characters, some of these omissions even alter the games ending, so yeah, there is quite a bit of replay value for it, especially for an FF.

I'll give you that the game's difficulty curve is bad, but the point of doing that was to make the game more accessible to new players, and you'll notice most games Square released after VI follow suit with rare exceptions mostly coming from Matsuno's crew (FFTactics,Vagrant Story) and this did help a new generation get into RPGs when VII followed the formula as well.

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I would agree its one of the best SNES RPGs, if anything cause the game is a bit of a watershed moment for the SNES. This is because most games on the system didn't bother with the type of cinematic and deeper story telling that VI attempted. I feel you can see a distinct difference to how games did certain things before and after VI, so I felt it was definitely a title that became a bit of a "eureka" moment for not only Square but other publisher's as well in that era.

I mean when you compare how Enix used cinematics and storytelling in DQV(pre-VI)
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and then DQVI (post VI)
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you see a huge difference,

same with the transition of storytelling from Battle Ogre
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to Tactics Ogre


VI introduced a means of using the character sprites as models to express more emotions and get more out of the story. It's visual style finally broke Final Fantasy out of the largely High Fantasy setting, introducing sprites dressed in Victorian era garb and showing off obvious 2nd Industrial Revolution architecture and machines (along with the sprinkle of sci-fi stuff the series usually has) which no one really did before then. It also integrated gameplay with story sequences which had never really been done before with stuff like the opera scene and the fishing mini-game letting the player have more immersion in the plot and characters that is largely absent from JRPGs.

Chrono Trigger and the PS1 generation FFs owe a lot to FFVI for raising the bar in how a JRPG can tell a story and build a likable cast of characters. So damn straight its one of the best SNES games if not one of the most important.