I do, in fact, prefer FFT's art because it looks like classical time period art. People wear plain dresses, regal men carry swords, there's no fancifiul regalia or bright colors for show -- they're akin to actual portraits. FFTA's art looks like comic strip characters, mostly because they're the opposite of FFTA's style: flamboyant colors, exaggerated features, and they all look like kids. I may hate the game a little more because I favor the original, but when it comes to the art, it's quite clear to me that there are two different styles. I prefer the "adult" kind.
And I don't see how anything looks like "Mr. Potato Head," either. Even the summon art is different from the characters', and even I wouldn't go so far as to say that FFTA's art looks like a simple cut-and-paste job.