I think we can all agree that the most objective, universally agreeable metric for the relative quality of particular versions of this game is the Umaro Scale.
It goes like this: Umaro, being unanimously agreed upon by all individuals of good taste and good sense as being the neatest, best, totally awesomest character in the entire game of Final Fantasy 6, should be the standard by which all versions of the game are measured. We therefore formalize this standard in the form of the Umaro Scale, defined in terms of relative values of Umaro Points, henceforth written as UPs (that's pronounced "ups" not "you pees" for the more sophomoric in the audience).
We normalize the Umaro Scale around his utility in the SNES release, declaring that, as the baseline, the SNES version of Final Fantasy 6 registers at 1.0 UPs on the Umaro Scale. We further break down this metric as follows: in the SNES release of the game Umaro has two (2) unique relics in the form of the Rage Ring and Blizzard Orb, along with a further two (2) equippable items permanently equipped on his person in the form of the Bone Club and Snow Muffler. These four items, respectively, each constitute one quarter (.25) of a point on the Umaro Scale. The Game Boy Advance release adds an additional unique Relic for Umaro, in the form of the Bone Wrist, effectively adding an additional .25 UPs to its total. At present it is impossible to attain Umaro or any of his items in the mobile version, rendering it unmeasurable on the Umaro Scale and therefore qualifying it for a default assignment of 0 UPs.
To conclude:
Mathematically-defined, objectively-determined relative quality of various releases of Final Fantasy 6 as defined by the Umaro Scale:
Super Nintendo: 1.0 UPs
Playstation: 1.0 UPs
Game Boy Advance: 1.25 UPs
Android/iOS: 0 UPs (at present; subject to revision in the event that Umaro becomes attainable)
I can foresee no objections to this scale that would stand up to even cursory scrutiny, and so have taken the liberty of submitting it to the International Organization for Standardization for ratification as a universally-accepted standard for measuring relative qualities of differing releases of the video game Final Fantasy 6.
I am certain that its approval is imminent.