One thing to keep in mind is Square didn't get their rep for making graphically impressive games until FF7 came out.
FFIV didn't look that great... FFVI was a good-looking game but nothing mindblowning.
I disagree strongly.
Squaresoft was already well known for having top-notch graphic and sound design all through the 16-bit era. All the FF games, Seiken Densetsu 2 and 3, the Romancing Saga games, Chrono Trigger, Bahamut Lagoon, Front Mission, just to name a few.
FFVI was the first SNES game to use all of the systems 256 color capabilities, which was a graphic marvel at the time.
I can still remember looking in GameFan in early '94 and being absolutely floored when I saw stills of FFVI.
Compare Sega's
Phantasy Star IV to Square's
Final Fantasy VI. They came out within 4 months of each other (in Japan, at least)
to
On a similar system to FFVI, here is Quintet/Enix's
Illusion of Gaia (released within 5 months of FFVI):
I didn't even post an image of a battle screen, which is where FFVI could really shine graphically.
The amount of colors, texture work, character models (and animation, albeit simple), and effects outclassed any other console RPG at the time- and stood pretty damn well against non-RPGs, too.